Why are t-shirts/merch lines so long now?

In my early days of going to concerts in the 90s, you just went to the merch table (or more than one at bigger shows) and bought a shirt. I don't remember there being long waits. Now shows often seem to have enormous lines. Why? You'd think with tap to pay things would actually speed up as people aren't fumbling for cash, but no. Is it more people wanting souvenirs of shows?

Related side grumble: wish bands would do a better job stocking the more popular tour shirt sizes. Sucks when you want large and all there is is medium and extra large.