Just because there are lots of NPCs in the game does not make the game feel alive. I know Kingdom Come Deliverance is on a whole other level and better than any other open world for NPCs but play that game and you will know what I mean how that game is alive. That game also has a lot of ways to complete quests unlike CP2077. For example in KCD every NPC has a role they will do. Like every day a peasant will wake up, go put on their clothes, go eat, go to the fields and farm, then go to the pub and then go home to sleep. This worked for almost every NPC including main ones. So if there was a tough guy you wanted to kill but couldn't handle him in his full suit of armor you could simply track him to his house and kill him in his sleep or even if you did wake him up by being too loud he wouldn't have his armor on and be in his night time clothes making the fight easy.I agree with ipaine that the world feels quite alive and full of NPCS, so I'm not sure where you're getting that from again unless the people you're watching on Youtube aren't actually trying to play the game and ride the clickbait hits about bugs they've run into, or purposely re-created so that they can again ride that clickbait hits on youtube.
In contrast CP2077 there are so many NPCs including shop vendors that have no interactions except one liners with and 99% of NPCs just walk back and forth on their set path or disappear behind you. In the Witcher 3 at least every shop vendor you could buy and sell and most you could play gwent with. IN CP2077 they are just empty husks with no purpose.
For a game that was so hyped and in development for so long I expected better. It doesn't help the CDPR promised so much that just isn't there.
"The city streets are bustling with crowds of people from all facets of life, all living their lives, with a full day/night cycle."
"According to new CDPR interviews, Cyberpunk 2077's new real-time AI systems will allow for incredible dynamism. Thousands of NPCs will have actual daily routines throughout Night City's six districts, including a ton of robust and varied characters with cyborg implants, unique designs and animations, and day and night cycles." All these things KCD has done yet is a much smaller dev team and in much less time.
Here are some examples.