I’d rather live a shorter life with some freedom than spend all my life indoors or on a lead. Just because the cat got to 16 doesn’t mean it wouldn’t have rather have only got to 10 going out. A lead doesn’t compare to running and jumping and chasing they can do without.
But you're not a cat. You're an adult human with the capacity to understand dangers and avoid risk. You also have mental capacity to make decisions for yourself because you understand the dangers and whether the benefit of say, getting in the car is worth the risk of getting in an accident.
Cats only have the IQ of a 2-3 year old toddler - and you wouldn't send a toddler out to run about in the street unattended because it's more fun than playing indoors. They don't understand the dangers of being outdoors and many get sick and badly injured running in the roads.
We don’t lock up our children just because it’s safer for them to be inside.
But we don't let them run off without us either. They play in the garden (or in parks under supervision) where we can see them and keep them safe, because we understand that they can't assess risk and danger for themselves.
People shouldn’t have pets if they can’t give them as near natural life as possible and would sacrifice that just because they don’t want to lose them.
Would you argue the same for dogs? That they should be allowed to run free no matter what, because keeping them on leads and stuck in houses is unnatural?