Different ROMs for Lambda 8300

[David G]

The first version of Lambda was illegal, that's why they changed the ROM to make it just barely legal. I suspect the real reason for lack of software was it was too late ... budget buyers could still get the ZX81 on discount, those wanting a better machine got the ZX Spectrum or C64. The 8300 was somewhere in-between

in the eighties the IBM clones were even more popular, not much compatible, and they sold quite well

they sold well because they were MORE COMPATIBLE than the new IBM models, which always broke some portion of backwards-compatibility. Unless you are thinking of the workalikes e.g. DEC Rainbow with MS-DOS, which sold well until the clones came along. Compaq was the one that turned the equation around, and hundreds of 100% compatible clones followed