You are free to make as many grapple attempts as you want, as long as the conditions for a grapple are fulfilled. Teleporting 400 feet away or even casting the Fly spell is an excellent way of interfering with someone's ability to grapple you.Grappling is, more or less, free. Spells are generally finite. There are situations where the reverse is true, but they are less common.
Monsters don't really need to use escape spells since their size, strength, and special abilities tend to become more potent as their CR increases. Being two size categories larger than someone alone makes you immune to their grappling.See above. I usually see arcane casters with approximately two escape spells prepared. Many monsters have little in that department.
My apologies. I thought "did not seek cover" referred to the Wizard.Exactly. As long as your opponent is that far away, the javelin serves a purely ceremonial purpose. I suggest hiding in the basement.
I'm wondering what the environment is like in combat and skill use (although I do agree that spells/items can make these skills less useful).