I'm not a 3:38 guy per se, but I'm in the ballpark of being good enough to consider training full time. This is not an easy decision, especially if you have ambitions for a competitively sought after career down the road.
I think a majority of post-collegiate 3:38 guys are either working in a running store, have a very flexible work schedule (i.e. freelance web developer), or have the good fortune of mommy and daddy's sponsorship. A few may be in an Olympic Development group, but that often includes some shoe sales as well. They majority are struggling financially (or soon will be) and at one point or another find it very difficult to either afford travel to and/or get in competitive races. I respect the hell out of people who do this to chase their potential, but the reality is that very few advance to getting a legitimate contract and being a "true" professional. (I understand that's not what it's about, but it is a goal of all of these people and provides far greater opportunity for improvement.)
Perhaps I am cursed with my own pragmatism. I think about supporting a family a few years down the road, which I must unfortunately accept I will not be able to do through running. I'd like to do so through a career I actually enjoy and that's probably one I can't just step right into with no relevant work experience.
At the same time, I'm passionate about training and racing and feel I can get a lot more out of myself. A full time job makes that a lot harder. I will likely not be as good as I could be running full time.
I'm working full time and will continue to chase PRs until my body gives out. I envy those people with the skill set to do freelance work!