It would be complicated to figure out, but I wish historic preservation took into account "higher and better use"
For example, here in Pittsburgh, there was a plan to demolish
this historic church for a one-story drive-thru Starbucks. A strange choice, considering, there is a Starbucks in a hotel lobby literally a block away. Public outcry resulted in the church getting historic designation, protecting it from demolition. Now it's a vacant eyesore.
I absolutely think it was the wrong choice to knock down a historic structure for such a low-quality use. But now in the future if they say want to take out the Wendy's and Levin Mattress around the back, and use them along with the church parcel for a several-hundred unit apartment building...well, they can't. And this isn't even that theoretical, considering several large new-construction apartment buildings have gone in that corridor over the last decade.
Basically, don't knock down historic buildings to make way for a lower use (parking, strip malls) or an equal use (replacing a single-family home with a single-family home). But if there's a plan for a significant project, weigh the pros and cons. Consider if the developer has iron-clad financing or if it could go poof post-demolition. Look at how many jobs and housing units will be involved. How unique really is the historic structure?
But more broadly, in general I think we focus so much on historic buildings because everyone understands the "we don't build em like we used to" thing. If modern neotraditional styles were popular and affordable to build, and codes and zoning allowed for the same sort of finely-grained development, there would be nothing big about losing historic buildings - because we would be constantly building new buildings just as interesting.