She died in 1995 and Selena Gomez is apparently the most followed account on Instagram. So, I am guessing that Gomez is the better answer. Only old fogies know who the hell Selena Quintanilla was (old fogey here, so, yes, I know the name -- but it doesn't seem like the best explanation here).
That's certainly possible, but you have to consider that comparing Selena and Banksy is apt, while comparing Selena Gomez and an underground graffiti artist would be... bizarre.
> comparing Selena and Banksy is apt
How come?
Banksy bought graffiti art into mainstream and Selena brought Tejano music into mainstream?
Just a guess.
But was does Tejano music have to do with the internet or instagram?
The full quote is "In other words, kids these days are less Banksy and more Selena." I am familiar with both Selenas and side with Mz. It isn't a comparison, it is a contrast.
Look at the context. The previous paragraph talks about how kids are making a name for themselves on Instagram and Youtube instead of on the streets. Selena Gomez made a name for herself on Instagram and Youtube.
Selena Quintanilla is still the one more referred to by only her first name. Despite Selena Gomez being much more relevant in the mainstream, a Google search for "Selena" still turns up results almost exclusively (excluding news) results for Quintanilla.
The context here is everything - including the zeitgeist. It's Selena Gomez.
(FWIW I'm not American and have never heard of Selena Quintanilla before who seems to be a very US/Mexico centric person and The Register is a British publication so...)