My understanding of what it meant to have sente in this situation is that white can now consider the relative value of a move locally to the value of a move somewhere else.

White retains the option of playing locally as you suggest,

The thing is that equity in a joseki does not mean equality. Rough equality depends upon each player playing the same number of stones locally. Equity does not. Black started off with around 14 pts. in the corner. After 10 more moves, 5 by each side, we expect the value of the corner to remain around 14 pts. (Actually, because Black cashes in the komi as play proceeds, we expect Black to have gained around ½ pt. or a little less in 10 plays.) If Black had taken sente in the joseki, then, with correct play we would expect the local result to be around 0, plus a little bit for Black.

The longer the joseki, the less, on average, we expect each play to gain, until, in the extreme, each play gains nothing. In that case it does not matter whether White retains sente or not. (This is actually an argument in favor of tenuki, BTW. )

I think I see what you are saying now. This is a very interesting way to think about what is going on in a joseki. I'm going to have to think more about it, but this is very helpful.