In Brazil, during 1990 - 2000, telecommunications were a highly regulated market. Due to difficulties to enter the market, there was not that many companies around, and outside big cities, phones are mostly inexistent or too expensive for the average customer.
I remember that in my city (100k people) there was only one option, and in my mother’s city (5k people) there was no option.
After ~2000, the government did a big deregulation, making easier to other companies to enter in the market and do investments. A few years later, we got coverage across the entire country. For example, in 2005 my city had 5 options and my mom’s city had its first option. At this time my family finally could afford paying for a phone plan.
So yeah, excess regulation can harm markets, and deregulation can be good. Finding balance is key here.
I mean, you said that deregulation has no benefits, I just gave you an example that disagrees with your idea. It does not matter other Brazilian problems in this context, I could take any example of any place to prove my point.
It does matter because you cannot isolate the effects of regulations from the corruption, violence, etc… All of which are huge issues in Brazil.