And you thought the original Type A 1922/3 Austin Seven, with no electric starter, no carburettor choke, no dampers, no fan, and no speedometer, was Spartan? Yes, it was to be quickly improved in all those areas, but for fun, let's take a look at two examples of what was being offered to impecunious motorists at the time, two cyclecars, the Grahame-White "Wonder Car" and an earlier make to give a flavour as to what was available during that time, the Adamson.
Reduced to a skeletal status, the "Wonder Car" was part car, part motorcycle, and part aircraft-inspired economy exercise. At £75 complete, it was £90 cheaper than the Seven after Austin had cut the price from £225 to £165, but this substantial saving came at a price: namely, almost everything. The "Wonder" had first been shown on Stand 25 at the 1920 Motor Show, priced at £164 : 4s : 0d  (or at £265 with a 7 h.p. flat-twin Coventry-Victor engine, so the £75 must have been a last throw of the dice to clear unsold stock.
Built by the Grahame-White Company at Hendon, London, the "Wonder Car" came from a firm better known for its aviation expertise and, hence, experience in building light yet strong structures. Its immediate predecessor was the Grahame-White 'Buckboard' of around 1919. This used a rear-mounted, air-cooled, single-cylinder, two-stroke engine, bought in from Precision, with a bore and stroke of 74 mm by 91 mm and a capacity of 348 cc. It was rated at about 3 hp and drove through a two-speed transmission with ratios of around 6:1 and 10:1, then by a chain to the rear axle.
By 1920, this model had been developed into the two-seat "Wonder Car" and advertised at £75 complete. The engine had been moved to the front, and now rated at 3 to 3½ hp, or 3.3 hp in some contemporary listings. Influence from motorcycle practice was evident in the hand lever on the steering wheel for controlling the Amal carburettor and the use of a kick-starter to start the engine. Transmission was a two-speed chain-and-dog arrangement, with the same top-gear ratio of 6:1 but a lower ratio of 12:1. Final drive was by chain, with a clutch incorporated into one sprocket, though there was no differential.
As with many similar cyclecars, the chassis was constructed from an ash frame, braced in an aircraft fashion, with timber floorboards and light metal or aluminium body panels around the scuttle and the rear of the body. The wheelbase was close to that of the Seven at 6 feet 5 inches, with ride comfort depending on the flexing of the chassis; the undamped quarter-elliptic springs fitted front and rear, and with whatever flexibility could be extracted from the upholstered bench seat.
Wire-spoked wheels carried narrow 24 by 2¼-inch Palmer Cord high-pressure beaded-edge tyres. Electrical equipment was minimal: just a six-volt accumulator to run the small scuttle-mounted lamps. While a full-width windscreen was fitted, along with a perfunctory hood, there were no sidescreens.
The advertisement claimed a top speed of 30 mph and an economy of 50 mpg, the latter confirmed by contemporary tests in which, on a Surrey route (described as 'demanding' in one publication), 51 mpg was achieved.
In 1921, Grahame-White also offered a larger, short-lived 7 hp model with a longer 8-foot-1-inch wheelbase. This model used a 689 cc Coventry Victor twin-cylinder engine with a variable-speed friction drive.
Just about car-shaped enough to count, one can see how the industrial might of the Austin Works was able to wipe from the market such ingenious but uncomfortable contraptions.
For more on the "Wonder Car", and a surviving example, see the following; be sure to watch the video - and then give thanks that Sir Herbert Austin chose to take the advice of Stanley Edge and use a 4-cylinder water-cooled engine: See the following: https://walesclassiccar.wordpress.com/.../the-worlds.../...
and the cycle car in action: https://www.prewarcar.com/proof-at-last-the-grahame-white...
Grahame-White were not the only aircraft company to turn to car manufacture after WW1. After the 1918 Armistice, aircraft orders collapsed before civil aviation had taken off, forcing many British aircraft firms into motoring work. Sopwith's Hawker Engineering, Avro, Blackburn, Handley Page, Shorts and Bristol all tried their hand at car bodies, cars, and motorcycles..

Adamson was primarily a haulage company that  from 1912 until 1923, was also a manufacturer of cyclecars. To understand why the Austin Seven, essentially a conventional large car in miniature, proved so successful, it's worth taking a brief look at the Adamson cyclecar's specification.
At a glance, the two-seat Adamson might have resembled a proper car, but it was not: it was a pure cyclecar, engineered down to a price.
Steering was by wire and bobbin, with two lengths of wire wrapped around a pulley and connected to the left- and right-hand steering arms. This would have produced steering of the 'very direct indeed' variety, allowing the driver little opportunity to reconsider his intentions.
Then there was the leather-lined cone clutch. Anyone who considers the engagement of an Austin Seven clutch rather sudden would have found the Adamson's even more entertaining, even alarming, in its instant grip. Like most clutches of its type, it was either in or out, with no frivolous intermediate stage. To some extent, this abruptness was moderated by the final drive to the rear axle, which employed an eleven-foot flat belt. The proud owner of a new Adamson would initially have appreciated the belt's ability to smooth the thumping beat of the 1,000 cc twin-cylinder engine and cushion shocks within the transmission. Unfortunately, his enthusiasm might have diminished somewhat once the belt had bedded in and stretched, particularly when attempting to climb a steep hill in the rain.
Both foot and hand brakes were provided, although each acted only on the rear wheels. For strict economy, all the wheels were fitted with narrow, high-pressure, beaded-edge motorcycle tyres offering minimal grip. Just in case the steering and braking arrangements had not already commanded the driver's fullest attention, the tyres ensured that they did.
Lighting was confined to 'side and tail' lamps, apparently leaving the car without any form of headlamp, while both the hood and side-screens were charged as optional extras. Fair-weather and daytime motoring in an Adamson was not merely recommended and sensible; it was built into the specification..