It has been slowly happening but now appears to be in full swing, at least in the US. Now that they have such market dominance, TripAdvisor are becoming a full blown booking site and maximising their returns.
With Instant Book, or Book on TripAdvisor, consumers get the convenience of booking the hotel on TripAdvisor or in its apps without having to navigate to a hotel or online travel agency site. The hotels pay TripAdvisor a commission instead of paying for clicks. The commissions undercut those that they might have to pay to Expedia or Booking.com, for example.
More info on the transition is at these links
This will probably mean more business listing options from them for promoting your business above others. It will be driven by commission $$$ rather than traveller ratings and reviews. And an even more aggressive approach from TripAdvisor to selling you business listings.
If paying for business listings just make sure that you know if your return on investment is worthwhile. And maximise the opportunities that are available. Eg feature a special offer for your property as this provides additional exposure on the site.
You probably don’t like paying commissions but that is just the way the market is changing. Unfortunately you need to get used to it and maximise your benefit (or minimise the impact) from this change.