Does'nt a lot depend on development for new buildings? When rescue archaeology is required, the developer now has to pay. That wasn't always the case so I see it as a major advantage. Then the archaeos have funds and limited time to excavate what will soon be destroyed. Developers are legally required to notify when they come across evidence of ancient sites. That relationship needs to be managed because if it breaks down then developers may be tempted to just bulldoze evidence away and say nothing in order to save time and money.
When sites are not threatened - like the East Kennet long barrow, I am all in favour of leaving them intact.