ok. So I have always been told that the more advanced the music and musicians get, the more organic or flexible the tempo becomes.
Like the conductor could make slight adjustments to tempo and everyone would feel it similarly ect.
So if time and tempo can and will change, fluidly though, then does meter or any tempo marking really matter?
Aren't they just kind of a road map to go by, and really isn't all up to the conductor/soloist how to interpret the composer's work? So why don't we write everything in free time, and have the conductor do what he wants?
I understand that there has to kind of, be a standard for a certain piece, but I think music would have more variety if everything was up to the conductor. What do you think?

I understand the sentiment, but look at it from the perspective of the composer. When writing, the composer envisions (enhears? :-p) a particular thing with his music. He writes what he wants. While notation is not the music itself, but is a road map to create the music, it is still something that gives you all the information you need.

And while a more skilled ensemble will be able to follow slight nuances from a conductor better, that does not mean that the more talented you become the farther you stray from the written guidelines. There is a certain amount you can play with things (depending on the style . . . you can play more with Schumann than Bach for example), but cross that moving line and your interpretation will be laughed at and labeled illegitimate.

Plus, look at some advanced pieces (especially percussion, but not just). Michael McGlynn's "Dúlamán" is a choral piece that requires a very strict adherence to tempo and steady beat. It's not that you loose the need for tempo, beat, etc. as you get better; it's that you begin to work more with the music itself and get caught up less in those details. They are still very much there, but you don't have to consciously think about them as much.

I wouldn't say that these things become more organic or flexible so much as you become more attuned to the music itself, and as such, small fluctuations in these things will not throw you off.

I see what you are saying
When my HS band played Gandalf this year
(johann de meij) our director played with the tempo a lot
and Ive just hear countless variations on peices because the conductor wanted to interpret them differently