This is not true. All an encrypted (or locked) bootloader means is that you can't install custom kernels, which aren't required to root or flash different ROMS. It is only necessary to flash certain ones (like CyanogenMod) but plenty of other ROM developers make ROMS just as good as CyanogenMod using the approved kernels that the manufacturers provide. The Motorola bootloader still hasn't been cracked (& probably never will be) but there are plenty of great ROMs using the Froyo kernel & even Gingerbread ROMs using the kernel from the Droid X/Droid 2 Gingerbread leaks that was signed by Motorola.
Someone will still get the EVO 3D rooted, there will be apps that allow overclocking/undervolting to increase speed/extend battery life, & there will be ROMs.