My guess is that it's mostly advertising in franchise lifestyle places (like magazines) combined with the fact that it's selling a relatively low-cost service and works more by appointment than an open storefront. Sort of a cheap version of a business retreat or clown showing up at your birthday party.
Interestingly, a company as big as Square Enix has one, their "Trials of Bahamut" escape room in various cities.
Oh, and they aren't really new per se, it's just dinner mystery theatre without the dinner. Places have been doing that for decades.