Should a private company be allowed to sell a secure locked down device, with people buying it knowing that you cant 1) modify the bootloader 2) modify the os 3

Should a private company be allowed to sell a secure locked down device, with people buying it knowing that you cant 1) modify the bootloader 2) modify the os 3) sideload apps? To many people, the fault you find in the product is the added value that differentiates it from competitors.