What's the point of always "changing" the tomestones?

[Jandor]

I guess the transition phase might be a consideration, like if the new gear was going to use an existing tome you could buy 2K worth right from the start. So switching to a new tome makes everybody start at zero again for a new tier and they control your pacing a bit that way.

They should put the cap at the vendor end to be honest.

Let us gather 2000 tomes, but the vendor won't sell to us till next week once we hit 450 tomes. Would even open the door to splitting the vendors so we can have separate caps for Fending, Striking, Casting, etc.