This is one of these problem with multiple unsolvable issues:
- people are used to ad block and won't change
- the price is too high for part of the population (-> ad block for part of them)
- $1/month, $10/year would attract new paid account but not that much
- people can't afford/don't want a subscription everything
- users don't see any value in it
- a fraction of the paid will go ad block with the price increase
- people will circumvent the ad block block
- capitalism
- ...