If you're not interesting then physical security is less necessary because physical attacks are less likely and the consequences are lower. If you are interesting then you need physical security.
Unlock with PIN or with fingerprint? Obviously PIN is safer because we leave fingerprints everywhere. But threat modeling comes into play.
I know of a guy who got his iPhone stolen at a party and started receiving email notifications of account changes. Did the thief use NSA grade decryption techniques? No, the phone was protected with a PIN. The thief likely kept an eye on people unlocking phones and stole the one he was able to spot the PIN for. The inferior security method (fingerprint) would have prevented unlocking the phone and maybe made the theft less interesting.
It's always a tradeoff and one has to decide who's wanting to protect against.
Okay, so imagine you're in a country where homosexuality is illegal, but you still are trying to live your life as a human (the majority of which seek companionship).
"Oh sorry, not only are you ruined when they kick down your door, but everyone you've ever networked with is at risk now too maybe try not living there ha ha goodbye!" is not a story.
What's more, I just want to point out Apple and Google have been trying very hard to make devices which all but the most resourced individuals cannot break. As you implied, some access weaknesses exist to this day, but right now for desktops and laptops this "welp I guess you deserved this because you weren't careful" attitude seems to rule the discourse.
It's shortsighted, it's regressive, it's unhelpful. And while I cannot know your motivations, I know many folks who are so paranoid that Intel and AMD might have backdoors in their boot integrity verifiers that they're willing to ignore people desperate to keep secrets on that principle rather than try and make an actual best effort at security.
I lock the door of my house. Most people do. That helps against burglars, which is my threat model. It doesn't help against police with a warrant in some countries, maybe warrantless in others. If somebody wants your data so badly to kick down your door, maybe they are willing to use workarounds even less pleasant than https://xkcd.com/538/ There are techniques against that, compartmentation (is that the right word?) and others. The more farsighted is trying to change how a country works. Long and risky though.
Also, a plumber would probably invest in mechanic arms to prevent possible injury when working before it comes to preventing physical access to his/her computer.
In short, it's a question of effort and priorities.
A default setting change protects me from black hats walking around with special cables in Starbucks? Yeah, sure, why not. Me having to carry my ultrabook in a locked steel case? Not so much.
The saying is, saying you don't care about privacy because you have nothing to hide is like saying you don't care about free speech because you have nothing to say. The analogy works because they're actually analogous -- it's a private right vs. a government imposition in both cases.
This isn't that.
Doing things this way has costs. It once was that if you forgot your personal device password then you take it to a computer tech who uses "physical access=root" to reset your password or recover your files.
If you make that not practical anymore, how do we solve password recovery? "You lose all your data" is not something people want to hear. The current solution seems to be to backup everything into The Cloud. But I thought the idea was to improve security?
Meanwhile you can't actually know if a state-level attacker is able to penetrate the likes of Secure Boot until it's too late, and the chances are that they actually can. Which means interesting people still need physical security.
From the corporations' point of view, there are multiple customers to satisfy for each device shipped, not just the end user. My point being that this risk analysis is simply more complex than any single end user's needs.