[DIYbio] Pathway to elective cosmetic gene therapies?

Hello,

I've been reading about gene therapies and noticing there is a lack of FDA approved gene therapies, granted most of the proposals put forward are solving some serious diseases,
but I was wondering if anyway has given much thought to a route to getting to commercialization with an elective cosmetic gene therapy?

If a gene therapy uses a non-replicating, safe vector, such as an engineered Adeno-Associated Virus, with the modification resulting in a low immune response in clinical trials.
What hurdles are left?

In Andrew Hessel's talks about cancer treatments, he eludes to the possibility of individualized therapies that could forego some, if not all the regulatory hurdles.
I can't quite see how this possible?

I understand this may be nuts to ask in a DIY context :)