They probably had people on the team who were nowhere near as experienced as people in studios like Rockstar or Naughty Dog. They were inexperienced, they were incompetent and that is what they could cook up in this timeframe.
Don't forget overly ambitious.
There is such a massive rift between what Cyberpunk does incredibly well (World design, graphics, and main-story writing) and what it does awfully (everything else). Playing the game is almost whip-lash inducing as you will frequently run up against something that is almost transcendentally brilliant, in the sense that you've never seen anything like it in another video game before, and then run smack dab into some awful, 2000s era, shovelware level shit 5 minutes later that isn't just bad, but
shockingly bad. Games rarely both succeed as marvelously and fail as miserably as Cyberpunk 2077 does, so there has to be an interesting story behind this failure: stuff that was dramatically cut, studio in-fighting, compromises, and etc.
Everyone is rightly shitting on the AI, for example, but I highly, highly, doubt that this is what CDPR had planned. The AI is so colossally bad that I guarantee you that they had a more interesting AI system that was in some degree of completion in previous builds that they ended up having to cut at the last minute for some reason and quickly mock up this monstrosity just to ship the game. Why they did this, I don't know. It could be to make the game work on PS4, it could be because they alienated their staff, or it could just be that whatever they had planned wasn't working so they had to cut it. However, the game has such promise that I hope they are able dig out and finish some of the stuff they may have half-way implemented and cut.
Who knows, though? It's also possible that none of this shit ever went beyond the planning phase and there was some kind of radical mismanagement going on behind the scenes which resulted in a rift between the high-level game designers and the actual coders. We are still close enough to the game's release that the recriminations haven't started yet, but at some point people who worked on the game will start talking about what happened behind the scenes. It's happened with every massively anticipated game that's been a mess on release.