>If the macro trend of hobbyist guitar playing has declined, I think it's correlated with its lack of prominence in current music.
>the top 20 songs do not have any obvious guitars
>It's easier for guitar novices to stay motivated when everything on the radio had lots of guitars in it.
How do you explain the booming popularity of the ukulele then?
I dunno. I'm nothing special when it comes to guitar but my first was a $50 pawnshop special that worked well enough. Then my second (this time an electric) was a crappy Strat knockoff, also used, for $150. Nowadays you can even get them cheaper from Walmart-type brands like First Act or online from importers like Rondo Music.
Sure, they're nothing great but they work for learning to play and screwing around with your friends in the basement or around a campfire (which is probably all you'd be doing with a uke as well if you're a beginner).
There was a major Ukulele boom during the great recession. A lot of people found themselves out of work and needed a way to fill their time, and as you say they are inexpensive compared to a guitar.
How do you explain the booming popularity of the ukulele then?