Why do people say old is better than new about everything?

Because the old stuff has had time to become much appreciated. Also, "legends", especially in music, are only recognized with time, ie: Michael Jackson, before he died. Or Amy Winehouse. Or even Mozart. There are probably many legends in the music industry right now but their impact on music will only be noticed later on.

Because they don't have enough energy to listen/play/do new things. They are programmed and compromised for old ones. I think regardless of old/new, anything which makes us happy and joy can be considered as best. No matter whether it is old or new. I say, enjoy old one, but try new one which is better than old one…

Because people can't accept change.

I agree that almost everything old is better and I'm 16. Literally all of my favorite video games came out 10-15 years ago. My favorite hip hop album came out in 1996 (Illadelph Halflife by The Roots), my favorite TV shows are Seinfeld, Friends, King of Queens, and Everybody Loves Raymond and most of them ended 10+ years ago. It's honestly true in my opinion.

Because it is true for some.

Either because they genuinely believe it or they can't adapt well and don't do good with change. I think Hip Hop was better in the mid-late 90s and early-mid 00s but that's not to say that the 2010s have been weak exactly but we haven't -- And probably won't have an album the caliber of Illmatic, Reasonable Doubt, Enter The Wu Tang, Things Fall Apart, ATLiens or Internal Affairs for awhile. The closest we've gotten to those albums since 2010 would arguably be MBDTF or GKMC imo.