Absolutely and that's exactly where you and I earn a living by forcing market prices back to realistic and more functional levels. There will also be times where we only imagine the disconnect when in fact the price is very well connected. I can think of situations where I've known full well what that connection was while having to put up w/ clowns crying about 'mean ol' stupid wall st.
Markets are not rational or irrational, they are arational. Sure, we can say the price of a given transaction is way too high. What that really means (if true) is that somewhere one guy determined that for him owning shares was more important than the money, and it also means that there was some genius that unloaded shares at a super price.
Thanks for your take on all that!