This has never been the case, and the existence of a smaller MacBook Pro since 2009 proves it.
The first several 13 inch MacBook pros lagged behind their 15 and 17 inch counterparts, it was basically a MacBook, but with aluminum instead of a plastic shell. Which is ironic, seeing as that’s literally what it started as, before the “Pro” was added.
There was absolutely nothing more “Pro” about those Core 2 Duo 13 inch MacBook Pros other than they were aluminum. Not exactly something helping people get their jobs done faster.
And this never really changed, therewas a 13 inch MacBook Pro in 2016 without the touch bar that was basically a MacBook Air in a MBP body, and the $1299 M1 and M2 MacBook Pro’s with touch bars, and the new M3 MacBook Pro are literally just MacBook Airs/iPad Pros just with the design of the MBP.