The disappearance of red phone boxes is a sad one for me. I completely get that they're probably nowhere near profitable, but as part of functional everyday infrastructure, you kind of expect them to just be there, in case they're needed. A bit like post boxes, which also seem to be getting torn up at an alarming rate.
I sometimes get a flash of happiness when I see a red phone box, only to have it dashed a moment later when on closer inspection it's been turned into a community library, or defibrillator store. The form is there, but the function has been perversely ripped away. It's like returning home and finding your beloved pet dog unceremoniously turned into taxidermy in your absence.
Not sure if this is an urban legend but I once read that a public phone box needs to be used 52 times a year to avoid being marked for disconnection, and I've often idly fantasised about finding a classic phone box to "sponsor" in this way, popping in once a week to make a wholly unnecessary call to a nonplussed friend or family member, all for the greater good and in the name of cementing British tradition for another fleeting year, dammit - but, hypocrite that I am, that remains a daydream.
It's a shame though, innit. A red phone box would have been an instantly recognised and intuitively understood sight in any village or town, in any decade from the 1920s to 2000s. Now - obsolete. And you could say the same about dozens of similar cultural mainstays that, well, haven't stayed. Print media. Post boxes. Postage stamps. Music on physical media. There's a real risk that physical currency could cease to be a thing in (some of) our lifetimes. All replaced with alternatives that are a bit more immediate, a bit more convenient, a bit less permanent and a bit less reliable.