A bit of napkin math.

How many are the white collar workers? 300 mln? even with $100 subscription each, the monthly revenue for your addressable market rises to $30 bln. If we increase the figure to half of humanity and they are 3 bn, you multiply it upto 10 and $300 bn monthly, $3.5 tn annually.

Now start cutting it down keeping in mind that not everyone is an office worker, does not need $100 plan, has access to cheaper models, could get ai through someone elses subscription or local models. I'm not sure how down it will get, but it can get down a lot and will have to be split among few players. At least for me it does not seem unrealistic that the revenue won't be enough for everyone.