The "old song being discovered through a meme" is an established phenomenon at this point, it happens all the time.
Of course, for an artist, it's like winning the lottery all of a sudden, without even knowing he bought the ticket. But like everything, it also has its downsides. For example, the sense of urgency to go viral at all costs that corrupts the entire music business today. In some ways, TikTok has partially killed the sense of making music for the sake of it. The paradox is that the songs that go viral aren't even those made to go viral, but those made with the passion of a person who simply wanted to make the music they like — see, for example, After Dark by Mr. Kitty

A song that's been released in 2015 and became a huge success on Tiktok three years ago