People grow and change at different rates and often in different directions. Sometimes friendships evolve with these changes and sometimes they don't. In this instance, you want to go out and be around new people often, while your friends would prefer not to be meeting new people. It seems that you really might want to let your friends know exactly what you are telling me. If you are gently straightforward with your friends about how their unwillingness to try something new is really frustrating for you, they may feel more inspired to do the occasional new thing.

You might also want to consider planning some sort of "exciting" event for your friends and yourself. By planning something, you may be able to take away some of the reservations that your friends may have about a trip to the city being a hassle or annoyance, and hopefully they will have a good time and realize sometimes these things are worth the effort. It might also be that your friends are more intimidated by new situations, so anything you can try to do to make them feel more comfortable might be helpful in getting them more excited about new people, places etc. You might also need to be patient with them for a while and try to understand why it is that they do not want to get out more.

It's always good to try to work through things with your friends, but if it turns out that they just won't budge, you might want to work to turn the new people you are meeting into closer friends. You just want to make sure that you don't let your current friendships hold you back from all the things you want to do. And luckily you can keep both new and old friends.