[Supernaut]

> It was manufactured to be as cheap as possible.

Exactly. The membrane keyboards weren't aesthetic choices, they were one of a number of compromises that were necessary to achieve the price point set by Clive Sinclair. He intuited that a sub-£200 colour computer would sell in huge quantities, and he was right. My (middle class) parents couldn't countenance the cost of a Commodore 64, but they were prepared to buy me a ZX Spectrum.

[bzzzt]

Computers were a luxury item then, beside that lots of people had no idea what to do with one too. Only the most computer curious people would spend around $900 (inflation corrected) on a fancy calculator ;)