It's a very huge problem, no doubt about it.
People won't spend the money to 'fix' their cats from making babies.
If vets would at least offer free neutering for male cats, it would help tremendously.
You know, have a day or two each month set just for that. It would also make for
a good training for vet students to have them do it a few days a month.
I won't ever have another inside cat. I have most my life but when Mr Kitty is gone,
I will no longer have a cat inside. I don't want to fool with the cat litter any more,
cat litter bags, cat litter container, can cat food, etc.
In reality, outside cats are not expensive. An adult cat is really only suppose to be
fed once a day. I feed the 3 outside cats, three times a day. They get the Special
Kitty cat food. It's cheap but it has all the necessary nutrients and they like it. In
the mornings they each get a little pile of the food, in the mid afternoon again they
each get a little pile of food, and then at night around 9 0r 10 pm I feed them again
each a little pile of food. They hunt and get mice and other outdoor critters including
small snakes.
Of course, I am in the country so people that live in a city have it differently. Many
cats in a city get run over and that sort of thing.
You could look for a no kill shelter and drop them off.