They don't need to have that full money, however. They pay another company a typical interest rate between 3 and 5% to post that bond on their behalf. So you probably need less than $1M per year to fund those bonds.

The bigger issue is that it takes lots of time and effort for back-and-forth with each state to get authorized. One person has maybe the bandwidth to obtain compliance with up to 3 states at a time, and this is for someone who knows the legal background very well. So you need to staff a pretty large compliance department off the bat to become compliant before engaging in money transmission (and thus before earning revenue). That's hugely expensive.

source: I work for a money transmitter.