1,2) don't turn a profit, especially if most users are indeed not using new reddit. It's probably better to let users customize new reddit and figure out a different stylesheet. Some 3rd party apps do this.

3) I'm guessing this isn't easy to do because there's still some division of ad revenue between the creator, the ad provider (usually google/apple in this case), and Reddit.And if you require ads and all ad revenue to go to reddit... well, there goes any incentive for others to make apps. 3rd party devs aren't charity cases either.

4) that is good for showing a profitable quarter, not good for generating actual revenue.