I don’t think they make as much as they claim - good friends of mine were bakers from their teens to retirement. They did proper cakes and everything in a trendy part of London. Their margins were very narrow - not the kind that would allow multiple jaunts abroad. Also, they had very long days so even if social media was a thing, they simply wouldn’t have the time to tit about as they needed to work.
I suspect a lot more of the girls’ lifestyles is funded by dads / partners than £14 brownies that sell out within 20 mins (which speaks to a daily cap - don’t want to burn out on a glorified hobby, not a living).
I asked about the Stork and spread vs butter and my friends said they found cakes made with Stork kept better in a freezer, lasted a bit longer when decorated but it had a more neutral taste that could be covered by the filling. Oh, and it was infinitely cheaper than butter. They goggled at the business model based on Tesco blocks and pre mixes.
I personally wonder if the complaints regarding the cake jars could be down to them recycling old freezer cake that would otherwise be thrown. Chucking in a mess of frosting is an attempt to cover sponge that is just about to go stale.