Is replay really that hard to do in game?

Hence why this nmeeds some thought. Your definition of replay isn’t the same as others, and there will be different perspectives. So, for example, if Asobo delivered a capability matching the current freeware/payware capabilities, you would be unhappy (whihc is your perogative of course, not criticising). This is why this isn’t a straightforward thing at all.

By the way, are there other mutliplayer games that record what everyone does and replays the whole thing? I can think of team games like FIFA or Rocket League, but not anything particularly open world.