There'll just be another plateau if and when you get over the current one! <grin>
I like what Joe Friel says. He actually is talking about older riders now since he is one himself. But except for the things old age is doing to us, you still pretty much do the same things to achieve any goals you have for your cycling. I don't race, nor do I really train. I just find out what on my rides I might need to do better and then figure out ways to get better doing it. Usually it involves more riding!
And identifying and stating your goals will be invaluable to getting help here and elsewhere. A little more tangible than you just want to get better or maintain what you have.