Indoor vs Outdoor cat - Why are there more "house" cats now?

I know someone's indoor cat is 18 years old now. But you know, usually animals in captivity do live longer than their wild counterparts. It still does not cover the fact that their wild relatives are more healthier, stronger. I can imagine that with proper food and care, animals in captivity will never need to go through the trouble of looking for food, and being constantly starving and maybe in fear of natural predators, but I can also imagine how the animals stay indoor throughout their life are physically weaker and easier to get sick. Just like humans who rarely go out to participate in outdoor activities.

There is also the fact of "freedom". Being locked up inside the same house for life sounds horrible to me lol.