Would Vampire the Masquerade be a better game if you could just drive between setpieces in a fully rendered city instead of having a loading screen? Probably, but it would also increase the development workload by an order of magnitude for what would effectively be a gimmick that wouldn't really add a lot to the game.
And even outside of RPGs, there are countless adventure and FPS games without vehicles. Doom doesn't have cars, neither does Tomb Raider, Devil May Cry or Resident Evil.
Of course if you're thinking of something like "GTA V, but you can't drive cars" then obviously that seems very tedious, but if you build the game with this constraint in mind it shouldn't be much of an issue. Then you can focus on other aspects of the game.
Cyberpunk is clearly not at its best when you're in a vehicle, and there's no telling what else they could've implemented and finished if they had cut it entirely and focused on other aspects of the game instead.
The reason why it's tedious is because the map is built around cars. You can't go very far without encountering a road. This makes it fairly hostile to be a pedestrian since you're relegated to walking on sidewalks (or in front of traffic if you're daring).
A city built around pedestrians could have a much different environment, like open green spaces, cobblestone paths, proactive NPCs engaging in little dialogues with shopkeepers, people trying to sell you stuff on the streets, etc. A real "night out on the city" vibe that I don't think any city-style game has tried going for yet.
This is one of my biggest gripes with the game. You literally have self driving cars built into the lore (and the story - Delamain) AND flying cars (Trauma Team, police officers), why the hell does anyone care about owning a car or driving it? We have cybernetic eyes and our cars drive/fly themselves and we still need to put up LED traffic lights?
Sure it makes sure in the outskirts to pick up a 4x4 offroader and do some cool desert driving for side missions. But in Night City? It should be modeled after pedestrians, and it is in some cases, but the road layout clearly looks like it was modeled for a city in 2012 and not 2077.
Don't get me wrong, I'm loving the story (watching let's plays no less, I don't have the specs to run the game myself). I think it's a great game despite the bugs and performance issues that will unfortunately haunt CDPR for a great deal of time. But some of the plot holes are just so deep, it hurts to think about because of how much better the story would be.
For example, I know the breaching minigame where you have to click through the matrix to complete the sequence of hex codes is unrealistic and not how you would hack a real computer. Obviously, I'm not going to gripe about that, it's a minigame inside of a video game and it's meant for entertainment, not realism. But, come on, you introduce us to cybernetic eye implants and we still have to use a 27" monitor to check our email? Why would you ever use a monitor again?