I do think that Michael chooses a troublesome example, in writing. The thing with writing is that it's not something that's forever barred to us. To say that the window is closed for me to become, say, a professional athlete is correct, but I don't think it's quite the same for writing. I suspect that Michael could write just fine, if he decided to do so. Yes, he'd have to work at it, but he'd have to do so even if he'd been writing all along.
Secondly, he seems concerned that his sense of style might have atrophied as well. But I suspect that what he'd find instead is that it's not his sense of style that has changed in the five years since he took up the pen, but that his style itself has changed. So, Michael, if you want to write, write. I don't think the window will ever truly be closed.
Finally, this reminds me of a passage from Stephen R. Donaldson's book Lord Foul's Bane, after Thomas Covenant has met the giant named Saltheart Foamfollower and joined him in a boat for the final part of his journey to Revelstone:
Foamfollower's question caught him wandering. "Are you a storyteller, Thomas Covenant?"
Absently, he replied, "I was, once."
"And you gave it up? Ah, that is as sad a tale in three words as any you might have told me. But a life without a tale is like a sea without salt. How do you live?"
Covenant folded his arms against the gunwales and rested his chin on them. As the boat moved, Andelain opened constantly in front of him like a bud; but he ignored it, concentrated instead on the plaint of water past the prow. Unconsciously, he clenched his fist over his ring. "I live."
"Another?" Foamfollower returned. "In two words, a story sadder than the first. Say no more – with one word you will make me weep."