Well, SAS has similar policy for quite some time already. Likewise Delta has set restrictions for STE+ travellers on economy in airports with contract lounges. BA charges for non-elites in business class on seat assignments.Emirates is already unbundling the business class offering, likely others to follow. I think in the future

Don't worry, things will get more interesting in the years to come.

I think that probably we'll also see business class fares coming up only only without lounge access, but also without food onboard. I see that also even using the full functionality of the seat could be further monetised: for example, using business class seat in flat bed mode on your seat could cost more than using it in armchair position. Or extra charge for blankets and pillows. Amenity kit surcharge.

For example, 1 USD business class base-fare, plus 1200 USD seat space surcharges (800 for the main and 400 extra for being able to extend flat), 200 catering surcharge (could be further split between food and drinks), 150 USD lounge surcharge, 80 USD fast track security surcharge, ad-free entertainment surcharge (25 USD). Gamification on meals could be thing as well: pay extra if you wish to have guaranteed meal, otherwise you'll be automatically assigned one, which you can't change.

That would enable airlines to make their products also harder to compare at OTAs, and perhaps drive more traffic their own websites.