Well, distributing the verification "back" would be nice, but it seems to me (from your post and elsewhere) that there are practical issues with that (and little to no impetus for pools AND for-profit miners* to adopt such a technology).
I don't think they are necessarily insurmountable, but yeah, missing data is hard to handle.
If a transaction 20k blocks before the end of chain goes missing, does that invalidate the chain?