The Spectrum came out before the BBC Micro and was a success because it was cheap, colour and could make beepy noises. The BBC Micro was much more an educational tool. The British Government put out a list of computers that were appropriate for schools and Sinclair was furious his computers weren't on the list, so he offered schools a ridiculous deal that some took, but the majority of schools used BBC Micros because of the BBC programmes. Really it was a very bad move and many schools continued by using Acorn Archimedes computers instead of PCs even as the Internet was taking off and it was quite clear that we were facing a Windows world.

My recollection is that schools adopted the BBC, but consumers bought the Spectrum. Later on (as I recall) the C64 took an increasingly large share of the market.

Interesting. The BBC was, in many respects, very sophisticated for the time. It makes sense the simpler, cheaper, Spectrum made a larger splash in the home market.

In Brazil, the home market belonged to Apple II clones at first. Small offices split evenly between TRS-80s and IIs, with a small participation of CP/M machines. Later the home split between IIs and MSXs, losing space progressively to IBM clones. And then it all became this dull x86 world we now know.