I believe the infatuation is for more than just TRCs. It is the total look of the package (I know, TWSS)! One of the attractions to many players is the beauty of the products PRS produces. To make it a bit more beautiful (in your eyes) for a low amount of money is almost a no brainer for many! Hell, there are even people who will turn their guitars into fashion statement pieces and leave the rod exposed ;~))
I have changed the TRC and tuner buttons on two of my 3 PRSi. I have changed the knobs on all three of them. All in the name of it being a more pleasing piece of art for me, and I am what counts ;~)) Here are my upgrade shots.
Custom tuner buttons and TRC on L and C, R is stock
Ebony knobs on L and C, Ebony pup rings on L, gold/green sparkle knobs on R
Custom cover plates
Some like to make their guitars "their own" by doing some customizations ;~)) Call it infatuation if you will!