Your comment reminded me of the time I tried to connect my new phone number to my accounts, but had trouble with Amazon and AirBnB because the last guy with the number forgot to update his accounts.
Amazon told me it'd have to delete the old account before allowing me to connect my new number.
That's not even the worst one though.
AirBnB gave me no other option than to log in to the other guy's account through nothing but the SMS recovery code (which came to my phone since I have his old number now), starting the account recovery process from within his account, and then removing the phone number from his account.
After logging out (and closing the private browsing window and turning off the VPN), I was then able to link the phone number to my account. (And yes, I tried everything else -- from within my account, it told me "Sorry, this number is linked to another account")
Never had a problem with AirBnB or the new phone number since then though!
Considering companies can easily sell new copies of games after 2 years, I'd still be fine with a longer period of time. I want developers to make money.
I've seen a Kickstarter that would open source their game after 2 years if they raised $4.4 million or so. They didn't reach that goal, but they open sourced the previous game in the series after about 10 years.
For just removing DRM, I think somewhere between 2 and 10 years is the sweet spot. I mean, I've still got 10-year old games on my list I'd be willing to buy, haha