I only know of one day ticket fishery near me where I could get a bus to any where else would need 2 or 3 changes plus a taxi ride. All the places I fished years ago are no longer on bus routes those that are have waiting lists only filled by dead mans shoes..
So public transport would need a big upgrade to serve the general public, it would also need to by cheap and reliable.
I appreciate that, a lot depends on where you live and the quality of the transport and i wouldn't want to have change all the time either. But I found about 10 places, river canal and commercials/day tickets. The river and canal stretches are 30 min rides and the buses run every hour; I dont know what the fares are but I am sure it would not be much different if I added up the cost of running a car these days. But I had too search it all out, I never knew they existed before I got rid of the car, I found them through word of mouth and started asking questions, looking at ordinance survey maps etc. It took time, I am just trying to say to anyone, have a good look first before they give up fishing, it may be there, they just do not know about it because they never considered it, same as me until needs must.
One example, a canal has a club sign on it "no fishing etc" so I walked along it one day and it did not say where the club stretch ended. I got hold of one of their cards and found out it where it ended, about the 5th fence. Above that it did not say so I fished it, have been for years and the farmer just ignores me. Only ever seen one other angler on it from memory and he was an EE. No one knows its free or the farmer is not bothered, he's not going to tell anyone is he and it's a long way off the main road so, everyone assumes it's all club water. The bus stops right by it and I just walk through the club stretch, about 15/20 mins. Its not great fishing but I have about a mile of canal all to myself apart from the odd dog walker or hiker. I am only saying this just to demonstrate you don't know whats there sometimes until you really look hard.
People just miss this stuff as it's not designated and never on the internet and never will be and that's why they are empty, I think there is possibly a lot more of it around but you have to look hard and find it.