2:30 is an eternity away from 2:03:38.

I am not thinking of dabblers; many people will do marathons after having barely trained. The goal for these people is just to finish.

I think 2:30 is achievable for a healthy, moderately talented man who is not merely dabbling: someone who is training correctly and has put in a few years of sustained, injury-free effort.

2:30 is still very much an amateur time. For example, I think that even though 2:15 or faster is professional-caliber it is still nowhere near being competitive.