I do believe the regular non-pro iPhones are the bigger sellers by a large margin.
You have to remember 95% of smartphone buyers are just regular Joe blow and Jane blow people that don't visit tech websites.
They make up the vast majority of smartphone sales. And don't give two ****s about 120 hz refresh rate or the pro model having slimmer bezels, and other miscellaneous upgrades compared to the regular version. People just don't care.
But they do care about saving a few bucks per month or out of pocket less money spent.
At the end of the day people want their smartphone to make phone calls send texts serve the web, do emails.