Yeah, material gain has certainly made me a thousand times happier. I haven't had to worry about an Electric bill in years. I used to have to navigate and memorize the electric company shutoff routine so I could pay as late as possible while selectively mitigating late fees and disconnect fees in relation to payday.
I can afford to go on vacations now. Take PTO when I want to. When my AC dies I don't have to just suffer until my landlord decides to do something; I can just pay the repair guy $700 to fix it and have AC in a couple hours. Eating healthier is easier; I don't have to stress in social situations about how run down or holey my clothes are. I have the luxury of being able to eat and survive if I am fired allowing me to be more confident in how I carry myself at work. (Meaning I don't have to kiss-ass when I am being mistreated). I have the money to travel if god-forbid my wife needs an abortion, or I can move away from bad neighborhoods very quickly.
The pursuit of wealth in and of itself as a measure of personal worth will not bring happiness, but let's not all pretend that money doesn't bring happiness insofar as it provides individual autonomy over their lives.
I agree with the OPs point that some older people may have just reached a level of material success that grants them the luxury of 1. Processing their existential dread through things like therapy; and 2. Live a less stressful life that comes with a certain level of wealth