This reminds me of my neighbor informing me, that he is leaving WhatsApp, because he heard somewhere that WhatsApp is going to give all of his chats to advertisers. He switched to Signal for about a month, found out that nobody is there and it's happily back on WhatsApp. All of this because WhatsApp allowed brands to store chats somewhere, the chats between the user and that specific brand. People often blow things out of proportion.
Unlocking bootloader/flashing isn't so easy for most people. I root every device I get, but for normal users this process isn't easy. Also some manufacturers aren't so friendly towards people unlocking bootloaders. I remember Sony lowering camera quality when you unlocked/installed Cyanogenmod back in Z2 times, or more recently Asus preventing you from unlocking completely.