Great proposal: One crash, 60 hours lost.
An ideal solution would be to reduce the required autosave interval, but allow the player to configure it more frequently again if he wants.
e.g. 1 year is required, but player can also choose monthly or bi-yearly if he is worried about crashes.
Best of all worlds.
Put it this way: What autosave frequency do normal non-Ironman players choose? I bet you find that 90% do not use monthly, because it is too much saving. So saying that monthly is required to prevent against crashes is not correct.
Personally I only have five-year autosave on my non-Ironman games, then I also save manually now and then when something important happens. And I have only had a couple of CTDs - in hundreds of hours of gaming - which lost me a year or two in total.
It's a balance between regular inconvenience/slowness from more regular autosaves, versus peace of mind against crashes. When crashes are rare, most people will want less frequent autosaves to speed the game up and reduce inconvenience.