Decker looks like he's in his early 30's in TMP to me do his starfleet career has lasted 15 years roughly and out of those 15 years he's spent 3(?) overseeing the refit of the Enterprise and, in my canon, as little as six months onboard the Enterprise. That still leaves hmm plenty of career on other ships, he can still be first officer on the USS Boston and lots of other vessels in that time. I'm not excluding him from another ship or ships.I prefer it if he wasn't an Enterprise officer, because there has to be more to Starfleet than just the Enterprise. It can't be that only Enterprise personnel ever achieve anything and every other ship is just there to get destroyed. There must be other ships whose officers achieve success and establish their worth. It shouldn't all be centered on just one ship.
Does it not make sense for an ambitious young officer to aim for the highest and, like it or not, the Enterprise appears to be the most prestigious mission in starfleet. There were many ships in the British navy but I bet lots of officers wanted to serve on Victory with Neldon. That doesn't negate what the Temeraire or the Bellerophon did.