if anything I wish more programs would take full advantage of it.

If every single application behaved like it owned all the memory on your machine, you would have a pretty horrible experience as they'll be basically fighting over what's available and likely hitting the swapfile. On the contrary, I do wish developers would care more about the memory footprint of their applications since they are sharing with all the others. Looking at it this way, optimising performance by using more memory aggressively (and thus reducing the amount of memory other applications can use) seems like a horribly greedy and antisocial way to behave, and thus it makes sense to use as little as feasible to give good performance.

(I'm assuming that the use case here is a browser that you have open along with other applications; if you only have a browser running, then it doesn't matter as much.)