They're not directly selling to teens, but they are indirectly selling them... and the entire big tobacco industry has been doing so for decades. You get them hooked early in life so you have a lifetime customer... that's been their tactic

Most adults who didn't smoke as teens never pick up the habit. Smoking lives on through peer pressure - something that matters less and less as a person matures.

It isn't shown as "cool" in movies like it used to be, so adults who are "set in their ways" are lacking most of the remaining peer pressure tactics that typically works for adults.

Wait for vape scenes in the movies. You can be reasonably sure there's a lobby group working towards it. How about a "FBE Teens try different healthful Vape Flavours"?

Yeah, it's an industry that historically kills it's best customers and needs a high intake (addictive) method of creating new lifelong customers. It's usually cheap, "cool", even easy for teens to start using any nicotine product but that usually creates a long term costly habit. They can't be directly marketed or sold to but that doesn't mean they aren't paying attention.

Same reasons as the other nicotine companies, new markets and new customers are always a plus since most of them will remain customers.