Yes it does improve rapidly and there is no doubt better technology than Blu ready to roll. So are supposed to upgrade entire collections every 5 years?
I think they can expensive, very expensive, but if they weren't there. Many here would be pleading, why don't the studios outsource movies they don't want to bother with etc and why don't we get this film or that one with all the bonus stuff that such a classic deserves. Most of the time...