"Now anyone can record high quality music at home."

Eh, to an extent. Audio production is a highly involved process. Few people have the equipment and knowledge to mic instruments & track sound properly, mix audio properly, apply professional-level production, master the tracks properly, master the album properly... It's not as easy as having a computer and some software.

You can get a pretty good sound at home now for sure but for professional albums you still need a decent professional studio. And even at home, getting good mics and hardware is still quite costly.

"A megastar can choose to record any of dozens of equally good songs."

There are famous or well-known (in the industry) songwriters that get chosen time and time again because they can consistently produce hits.