The only time the vehicals are moved is when the street sweeping passes by, other than that this Street is used a car storage.
Generally it's fine to park on the street.
Now you might have some weird local laws about where you can park, and for how long, but we don't here.
Now if the car doesn't have current registration, then it could be ticketed or towed, and there is likely regulations about derelict or abandoned cars. Also if it's obstructing traffic that's an issue. But if it's parked legally and gets moved occasionally, then it's neither of those.
Exactly why is this concerning you?
That depends on the laws where you live.
Where I live, you can only park on residential streets for up to 3 hours unless otherwise noted by street signs. Any car parked longer can be ticketed and/or towed. But it is a rarely enforced city bylaw.
It depends. There was an ugly van on my street that had to be at least 50 years old, in the same spot, every day. One day I noticed it had received a ticket for "no apparent activity", and had a bunch of writing on the tires. The ticket said something about it could be towed. I haven't seen it since.
So if you want, you could call the police, if you're the kind of person who likes to get into other people's business.
Seems OK to me. Are the cars road legal? What are the parking restrictions in this mysterious residential area?
What are the laws of the mysterious country where this residential area is located?
In the UK, unless there are specific parking restrictions on that street, then provided the car has tax, insurance and (if necessary) MOT it can be parked there as long as the owner wishes.
A move or two a week might be enough to prevent tow under 'abandonment' statutes/ordinances.
however, bad things sometimes start to happen to cars that just sit day after day with little real use and no owner nearby to watch them. smashed windows and lights, stolen plates, stolen or flat tires, graffiti…
Yep thats ok if there are no parking restrictions and the car is legal ie insured , taxed and not in a dangerous condition.
That depends on local ordinances. If the cars can be moved for street sweeping, what's the problem?
The city probably has a ordinance about the length of time you can park on the street. This might be something to ask the police and/or your representative on the city council.
Depends on laws in your town. Here it is 3 days. Must be moved