You can have a maximum of 200 neighborhood trading partners, but you're further limited to neighbors who are within a couple of rings on the fringes of your discovered territory.
We're still trying to catch up with the initial influx of lookiloos, who have now been removed because they weren't active. Once we've been through a couple of monthly cycles the new players will be sprinkled around a lot more, and the yep/nope vacancies won't be so drastic.
There are several Fellowships who would be happy to have you, and being a fellow ensures that you'll have a couple dozen reliable trading partners, plus whatever neighbors happen to be around.