If the cost of the account "member" for example $200
it is problematic to make many new Member's accounts
These spammers don't care about Members. The majority of accounts they use are Jr. Members which don't need anything but time and activity to be obtained (at least for now). If they put the process on a stream (and I assume that they do), they register a new bunch of accounts every day and evolve them quietly in boards like Off-topic just to avoid the situation when their previous bunch is banned. Thus they don't incur any losses.
Yes, while it is difficult to fight spam from accounts Jr. Members. The option of introducing Merit for them is already under consideration. But in this topic, I focus just on Member accounts and above.