In the UK, unadopted roads can be well-maintained, or look like this...
Nigel/Nigella lives on an unadopted road and got fed up riding his/her bicycle on the road as it was full of pot-holes. He/she called a residents meeting and made the following proposal:-
I will organise the repair of our road. I will phone some road repair companies and get them to quote for the repair of our road. I will call another residents meeting to tell you the pros and cons of each company and their quotes. We will then vote to decide which company gets the job. We will all contribute an equal amount to cover the cost of the repair plus a reasonable allowance for me, to cover my time spent.
Two outcomes come to mind.
1) Nigel/Nigella is a charismatic "people-person". All of the residents agree that Nigel/Nigella can organise the repair of the road and on his/her allowance. They later vote for a repairer and pay Nigel/Nigella the monies required. Nigel/Nigella gets the company to repair the road. Everyone is deliriously happy. Nigel/Nigella becomes head of the residents association. Nigel/Nigella becomes Mayor. Nigel/Nigella becomes MP. Nigel/Nigella becomes Prime Minister.
2) Nigel/Nigella is a nerd with poor social skills. One or more of the residents refuses to pay for repair of the road as they drive "Chelsea Tractors" (4x4s) and potholes are not a problem for them. The project is cancelled. Nigel/Nigella vows to not bother trying to make life better for people in future. The road remains full of pot-holes, like the one in the picture above.
The above scenario applies to residential roads. Who maintains non-residential roads? If no-one is in charge, all non-residential roads would need toll-barriers at entrances and exits, to collect monies for their maintenance. Alternatively, everyone pays road/council tax to some authority to cover the cost of road maintenance plus other essential services plus cost of organisation and lets the authority get on with it. "Top-down" authority has its advantages. We pay someone else to sweat the petty stuff.
Many years ago, life was simple. Things got done by individuals and groups of individuals. Nowadays, life is extremely complicated. To make things run relatively smoothly, we have laws, rules & regulations. Some laws, rules & regulations are good and some are stupid. The only way to get rid of the stupid ones is to vote for the person who pledges to abolish the largest number of stupid ones (and introduce the smallest number of new stupid ones) and hope that that person sticks to their pledges if they are elected.