Well, Dr. McCoy lived to at least 137, which seemed to be no big deal to anyone.
I'm certain there have been medical advancements, but IMO it just feels weird to use that as an excuse to have T'Pol show up in a TNG era story. And at that, how fun WOULD it be to do one where T'Pol would certainly be too old to contibute more than some wisdom and logic to a tale. Use time travel instead - everyone else does, plus it keeps T'Pol at her T'hottest.
Mark
Why?
Just describe her as going to the Ba'ku planet in the Briar patch for a decade and that's it.
Even when she would first get there, she would notice the effects of the metaphasic radiation after the first few days (probably more than enough to slow down the ageing and have her survive for the decade needed for her biology to revert to the previous younger state).
Realistically, the Federation should have advanced in medical science so much that by the late 22nd century, lifespan should have been radically extended (nevermind the 23rd and 24th century) via stem-cells alone for example.
It is possible that many people in the Federation simply don't want to live that long, or were really not encouraged to think like this.
But It's one of the less realistic prospects of Trek... whereas already in real life regenerative medicine with stem-cells will take off in the next 5 to 10 years.
And nanobots by 2030.
Radical life extension in real life is already talked about as being more than doable for humans using stem-cells alone... and we could have been using this for the past decade intensely.
Besides, weren't Vulcans described as living past 300 years?
If T'pol was 60 years old in 2154, she'd have more than enough time to reach Ba'Ku planet after Insurrection took place in 2370-ies and get restored to her younger self - though it never made sense that the effects of metaphasc radiation could not be duplicated by the best Federation minds who posses highly advanced scanning technology to boot.
The directors apparently needed a dumbed down reason to create viable drama (yet again).