I'm sure most of them don't have the money they like to make out they do, anyone can go somewhere nice or fancy for a day, take tons of photos or videos at different angles. You can go to a department store and rent out bags/clothes. There's even a fancy hotel in Paris that allows you to do a photoshoot there for an hour, and in LA you can get studios that look like private jets to hire out.
I wouldn't be surprised if they spend a few days somewhere making endless content and spread it on their social medias over the course of some months so reality looks much better.
Some influencers so genuinely have family money but the majority are not what it seems. Plus AI is pretty impressive now, you can cultivate any image you want if you have the skills and know how