That's why I've always been on the fence with this ECC thing. For servers it's vital because you need stability and security.
For desktops I think that for a long time it was fine without ECC. If I have to chose between having, say, 30% more RAM or avoid a potential crash once a year, I'll probably take the additional RAM.
The problem is that now these problem can be exploited by malicious code instead of just merely happening because of cosmic rays. That's the main argument in favour of ECC IMO, the rest is just a tradeoff to consider.