One thought to interject: assuming you have a relatively equal revenue/client over your client base, losing 1 account out of 3,000 is a lot easier to swallow than losing 1 account out of 12.
Higher client counts does not always equal greater profit, but in most cases it does insulate you from dramatic swings in revenue based on losing or gaining clients. That makes it easier to forecast and plan for the future, which in turn helps you manage almost everything better, and helps you sleep at night.
I say this as a guy who lost a client supplying 17% of revenue a few years back. I'd much rather have 100-200 clients each supplying .5%-1% of revenue than 5 clients each supplying 20%.