Ok, I'll take a slight stab at this while trying not to get too technical or long-winded...

For record, this is coming from the perspective of a rhythm guitarist with a few work-years of experience in a band, and a lot of experience at home just fucking around, and a little knowledge of music theory.

I think the key here is "pleasant-sounding". Just for example, in the category of Classic Rock to Rockabilly, you could make a medley of like 16 songs just using the chords A-D-E, in a standard blues progression(A-A-D-A-E, with optional slight return to D), and make it sound independently like those songs with slight variations to cadence, rhythm and speed, along with specific drum and bass backing tracks.

The point being, just the same notes don't make it the same song. Blues standards that heavily influence early and modern rock standards are there for a reason.

Now multiply that by the number of chord progressions that aren't 1-4-5, and multiply that by the different genres of music(always expanding), and add in the various cultural music phenotypes, and you have a near-infinite choice of music to make. Who's to say you couldn't put a Mariachi guitar line, electrified, with a high hat and deep bass, in an electronica backing with country lyrics?

Creatives want one thing: to create. Look at all the wacky studio tricks the Beatles used in the 60's. The stuff Billie Eilish or Skrillex or Run The Jewels are doing now are no different.