If you have become stagnant it is smart to look for a change. Might be a change in a coach or training or just an adjustment in attitude. It seems like you have already recognized this. I was not as smart as you. I ran between 2:33 and 2:35 for 4 years and that isn't good enough. I learned that 2:33 impresses your friends and family but not race directors or Elite athlete coordinators. There is NO difference between 2:33 and 2:40. You are not good enough to make a living or be in the discussion to make an Olympic Team until you break 2:30.
The Jenn Rhines example is a good one as she made a change and made an Olympic Team. She became relevant in the Marathon to Race Directors, Elite Athlete Coordinators and Sponsors after leaving Joe Vigil (an excellent coach). I still believe that Joe taught her things that allowed her to make the jump.
I don't know the Hillborn (former Hanson girl) and if she learned anything from her time with the Hansons that allowed her to improve but I do know that up to this point it doesn't matter as she only becomes relevant when she dips under 2:30 and becomes part of the discussion to make an Olympic team. Otherwise she will have an experience much like my own.