Not saying there arent a lot of functioning ones still, but failures are becoming more common. I bought a PS2 and OG Xbox this year from people locally, both worked great initially had laser failures for me within a week or two of use.
I've heard stories of people opening sealed PS2s and Xboxes and the lasers dont even work.
It's definitely a consideration to make at the very least.
I think in the future it will be very important to have modded laser based systems whether its an optical drive emulator or using the PS2 fat HDD/Network Adapter or Gamecube Action Replay.
With the original Xbox the system EEProm locks the harddrive to that system, when you have harddrive failure on an unmodded system you are hosed.