Not to mention that the Ataris were way earlier, and were at one point regarded as the MOST popular computer worldwide. That's why the learning platform PLATO was released on the Atari first.
Sure, let's shoehorn in lots of random computers from overseas. BBCs only sold to schools and education but not to most parents as they were too expensive. ZX Spectrums were Z80 based which isn't a 6502 processor. Apple 2 is mentioned in the article.
I think the point is that they sold fairly well compared to other successful machines of that era. They probably also outsold a number of popular game consoles as well such as Atari's 7800.
The Atari 400 was a much bigger technological achievement than the Commodore 8-bitters that were released later though. It deserves its place in history.
(it also was the predecessor of the greatest computer of all time: the Commodore Amiga ;P)
I don't think the historical importance has anything to do with sales numbers. The article mentions Commodore PET, of which only 200,000+ units were manufactured.
Four million units for the Ataris in the U.S. versus 5.7 million for the C-128 worldwide.
Seems pretty significant to me, especially compared with other 8-bit computers that people are always talking about on HN:
- BBC Micro: 1.5 million
- Sinclair ZX: 5 million
- Apple ][: 4 million