Men want beauty and vitality. Women want security and a stable environment. Why would anybody be surprised ? Don't be judgmental about a relationship that works for both people.
You ask why men do this. You also need to ask why women do this. Are these women idiots? I think they choose this life to not have to worry about where the next paycheck is coming from.
Older people have health issues. More pills more doctor visits. Not a big deal. Women by their nature are care givers so dealing with an older mans health issues is natural. I hear you, this is yucky. You need to widen your thinking. You can't say everything is working for you.