It's amazing the number of hereditary peerage titles alone that will become extinct in the next 30 years or so. Of the 41 peers without heirs, I counted only 4 (Westminster, Harlech, Hawke and Rossmore) under age 45.
It's true that a few titles will just decrease in rank (i.e., Westminster to a marquessate, Abergavenny to an earldom), but considering the only possible hereditary peerages in the next 2 decades may be for Charlotte and Louis, that's a pretty significant loss.
Brooke