I'm all for people working to improve their body, and there are many good reasons to weight-lift, but the idea that an average person might rationally choose to weight-lift in order to reduce their day to day struggle with putting strollers in cars and bringing boxes up from the basement is really just absurd. If your objective is to encounter the limits of your strength less often, paying for membership to a gym and going there multiples times a week to exert maximum effort in moving objects so heavy you can only pick them up a few times at once is clearly not the thing to do.

> If your objective is to encounter the limits of your strength less often

Less often in day-to-day life. Hitting your limits in the gym means that you don't hit your limits in day-to-day life as easily, so when you need to move a loaded bookshelf, or pick up your spouse and carry them across a threshold, or whatever, it's not a problem.

It's exactly like running so that when you need to run, you can. Want to make it easier to sprint when you need to catch the bus? Sprint more in general. Want to make it easier to climb the 5 floors of stairs to your office? Climb 50 on the weekends.

It's also exactly like anything else you would ever practice for. Need to do complex math at work that you don't understand? You should probably study. Annoyed that you suck at the piano? Spend time practicing at night. Is your broken Italian not satisfactory to you? Spend time speaking Italian.

It's not absurd to spend time and effort improving an area you want to improve. We practice specifically so we can perform when we need to.

(Also, the muscle mass put on when younger has a huge impact on quality of life when older. Strong people hold up better to aging in general. You might not have trouble lifting a 45lb jug of water now. Do you want to have trouble with that when you're 65, 75, 85? Putting on additional muscle early makes it easier to retain a healthy amount of muscle later in life.)