Then why aren’t more companies trying to get one?

It’s a huge undertaking to do. You have to prove to the US government that you’re capable of handling people’s money safely and that you’re providing a benefit to your customers. Years of internal systems audits with nebulous requirements. How do you do that without handling people’s money? You partner with a bank. It’s easy and relatively cheap.

But regardless of your ignorance on the subject, the original point still stands that Google is not gonna just “take your money”. Your money will always be in the custody of an actual bank.

The problem is that thing will be regulated like a bank, there will be a lot more scrutiny. And unlike Uber's "but we're just a tech company so we can disrupt by going around the regulation" tactic, doing this with banking would be a tad more challenging. Not necessarily unprofitable but it feels antithetical to the way Google usually works.