None of those things you propose i dont think have a chance of working atm.

First step would be to reduce inflation overall to 3% or so.

Where do you cut? Powers that be wont cut the proposal system since they are funding themselves through it, wont cut the witness rewards since most are witnesses, they wont cut curation rewards since they hold most stake.
Author rewards?

Second step would be to eliminate inflation-funded stake-weighted reward pool once SMTs are ready. Then, build a decentralized advertising and gamification platform with sustainable revenues. Kind of like what Reddit is doing.

That would be incredibly tricky to do and would probably lead to the demise of HIVE.
Reddit and Hive have vastly different appeals and the earning opportunity is a massive part of why folks come here.
The creators come to make a few dollars and the whales come to gamble (among other things) on the crypto market.
Remove the reward pool and you probably lose both whales and your creators. Hoping the reddit style gamification would work here is i think too optimistic.