We mod because it is the way of mankind, since the dawn of time man and I'm sure woman has wanted to modify their surroundings, appearance etc. The need for this can be aesthetic, aspirational or functional.
Aethetic - My cave seems dull, I'll get Ug to paint it. My hair would look nice with a golden circlet. Aren't statues lifelike, maybe I'll get one of my wife. Perhaps I should relic the B tuning peg on this strat.
Aspirational - Hey Ug got one of them wheel things...I should get one of those. Helen has a golden circlet, I'll get one too. If I had a giant statue of me everyone would respect me more. Wow Gibson are making a Pearly gates replica, if I get one I'll be able to get my tone closer to Rev Willie G.
Functional - Hmm if I use a heavier club it'll be better for bonkin' rabbits wiv. A circlet would help me keep the hair out of my eyes. I guess I could use a large stone to keep the door open and let in some breeze. If I had an ebony fretboard it'd make this guitar sound slightly brighter.
Yes as time moves on, things change, some for better, some for worse but now more than ever mankind continues to change things for these three reasons.
Here endeth the lesson, go forth and ROCK!