And "have to replace the motherboard along with the CPU" is the exact thing we're talking about here: there was no technical reason for Intel to make the earlier boards incompatible, they did it just because they could. Not that there was ever really a reason to upgrade beyond "buy the cheapest K series, set multiplier to 46-48x, done", but even if you wanted to, you couldn't.

It was an anti-consumer practice and said consumers never forget it (not that most tech channels don't provide active reminders of it). And those people are who everyone else asks when "I'm getting a new computer", they say "buy the competitor's product", and the rest is history.