I think Overwatch being free-to-play would be terrible because there is already a problem with smurfs. The devs, however, dont think that smurf are a problem.
The sad part is, Apex has absolutely set a new standard for free to play games and old paid games as well. Apex has released with a text chat for console (something the Overwatch community has been asking for since launch) and also a text to voice and a voice to text function for those who dont have a mic.
The ping system alone has set new standard for the entire gaming industry. I fully expect any new game that gas a ping system/com wheel to be at least as good as the one in Apex.
All of that on top of the solid, fun gunplay and overall game mechanics and polish, its pretty clear the only way for Overwatch to really compete in the future is going free to play. Analysts are already predicting this will be the case in 2019.
I suppose only time will tell, but Im guessing this summer/fall.