That's a pretty simple solution: if some service inevitably deteriorates in quality when run for a profit, then run it as a non-profit! I mean, isn't that how imgur actually started? The Reddit team wanted a decent image hosting so they made it and just accepted that running it would cost them money so they'll have to finance it from the profits of their main business. But then apparently profit-optimization kicked in...

There are quite a lot of examples in the past (all the way to the Roman empire) of rich people spending their money on community projects just because they wanted some things to exist, not to make even more money.