I had an Amiga for a while. You couldn't hook up standard keyboards and monitors to it, everything was just different enough to be incompatible. It didn't bode well for Amiga's future.
A "standard" keyboard here means "a keyboard made for IBM PC AT clones". When you put everything in context (and consider the Amiga predates the first 386-based PCs by a couple years), it made no sense for the Amiga to have a PC keyboard connector any more than it would make sense for an Apple II to have one.
The monitor issue is/was more serious, though not really an issue early on. The problem there was that the Amiga graphics modes would not work with many cheaper PC monitors, so we had to spend extra on expensive multisync monitors or Commodore branded monitors. And unlike the keyboard, that was something people wanted to upgrade.
Yep same nonsense on the Atari. Computer vendors back then really did frustrating things around peripherals. It was bad enough they were so expensive, but external disks, monitors, mice, RAM everything was proprietary, which made it worse. Eventually things settled on SCSI, then IDE, but there were many years there where it was wild west on standards for all of the above.
I just bought an Atari TT off eBay. It will nicely drive a VGA monitor, but not for its highest resolution (1280x960), for which it needs a special ("ECL") monitor. An adapter from that to VGA is $175 from a hobbyist -- almost as much as I paid for the computer.
