Music technology is a very broad field. There are lots of tools for songwriters, particularly those who have no real music training and no foundation in music theory. I don't think that would broaden McCartney's horizons much.
Then there are the "new shiny objects" in effects, with AutoTune being the most notorious in that class. If any of the Beatles did that, I might have to shoot myself in the head and I'm not even a big Beatles fan really.
But far and away, most of the music technology aims to make the old processes and sounds available at 1% of the cost. For example, I have a software reverb that was literally modeled from recordings and measurements made in the Abbey Road studio. Can't afford to hire an orchestra for $60,000 per session? There are great sample libraries for $2000 one time that, in the hands of a skilled sequencer can fool all but the most expert. Every aspect of the great studios is now available as part of a digital audio workstation. A person can put together something approaching what the legendary studios could do for under $10,000 now. Of course, the real differentiator is the engineers. A poor or inexperienced engineer can make the best studio sound like crap.
I have not seen any statistics, but I wonder what percentage of music streaming on Spotify these days has been produced in a (more or less) home studio. I personally know of some such cases. It would not surprise me if 10% of the streaming volume came from a little digital home studio.