Being a shadchan is hard work, besides that there is risk involved. With every shidduch you run the risk that, at best it will be a huge waste of time, and at worst the shadchan will gain a bunch of enemies. It is something that not everyone could do. I personally, cannot be a shadchan. I have called mothers and shadchanim with suggestions but I have always told them to leave me out and pretend it didn’t come from me. I am too afraid if giving the wrong advice to the dating couple so they would end up getting engaged, realizing it’s not for them, and instead have a broken engagement (or divorce) on my account. So I tell them the name and leave it up to the professionals to decide if it makes sense.
I know oomis doesn’t approve of children learning in kollel but any parent who is going to figure out how to shell out $500+ a month, can figure out how to thank the shadchan with this one time fee of 1000. Also, at the least a wedding costs 10k per side so 11k is not that much more.