On unlocked devices, you can install your own recovery that still has the option. So the removal doesn't prevent too much in practice. That ship sailed when Samsung stopped allowing bootloader unlocking on most of their phones.
What's interesting is that they tried hard to cater to the tinkerers before going in this direction. They "bought" (acqui-hired) CyanogenMod, contributed to open-source and had developer builds of their ROMs. I think they even had clean AOSP builds with the HAL and ABIs for their hardware baked in at some point. SafetyNet made it realistically impossible to daily a rooted phone in 2026 if you want to use banking, healthcare or most music apps, so it's safer for OEMs to tighten the screws on access to their hardware in kind.
My take is that they saw all of this as a risk to profits they could make from catering to regulated industries who would deploy their hardware en masse. It also didn't make sense to continue this investment after banks and healthcare put pressure on Google to step up privacy in Android, especially after Apple implemented Secure Enclave.
It's a pyrrhic victory regardless, in my opinion. If you're going to run a super-locked down Android device, you might as well go all-in with Apple. Their hardware ecosystem is better, their cloud services are better, they get first-priority for mobile apps, you get Blue Bubble Benefits, and their support (in-store and online) is on another level. Even MDM is better with Apple devices (through iOS Profiles). Shoot, even privacy-minded folks are better off on iOS with Lockdown mode.
It's ", including installing software". Lets not let the enemy of general purpose computing define the framing of the discussion.