there are many things that could happen acually,
if working for a long time overheat may cause some parts to stop working properly and could cause problems.
if the code is corrupted or the machine stopped reading it for some reason (overheat for example) that'll be a mess.
lets not forget that everyday new things are changed and added so it'll be a hassle to keep releasing updates for these machines everyday, it also take time so if the machine is encountering a situation that its not programmed to deal with that will also cause problems.
there might be other things but idk.