This is definitely true, especially when rpi is probably more popular than all other SBCs combined. I always feel burned about 2 years after buying anything but beaglebone, rpi or Jetson nano and can't find support. With rpi you can always find an up to date OS image (for the boards that need an OS).
If you use complex devices like cameras, you can probably find recent drivers and readme files for rpi. For other SBCs you will probably end up trying to adapt documentation for rpi and getting stuck because your OS is using a weird version of libc, or something like that.
If you use complex devices like cameras, you can probably find recent drivers and readme files for rpi. For other SBCs you will probably end up trying to adapt documentation for rpi and getting stuck because your OS is using a weird version of libc, or something like that.