Parents are beat. Both my now ex-wife and I had a burnout in the last 2 years. Work demands are higher than ever and our kids were also demanding. /edit The reason we're on our phones is that we're just too damn tired to interact with humans properly.
I suspect you meant this within the context of your own life, but historically that's almost certainly untrue. 50 years ago you likely would've had a job doing much more grueling work in less comfortable conditions. Conversely, your ex-wife would not have had an income producing job at all and after the age of 4-5 would've sent the kid outside for significant portions of the day.
More grueling work, but likely left AT work. No bringing work home with you. Likely less job stress at home as well, though it might be replace by financial stress.
My youngest is nearly 2 and can hold his own on a parking field, at a playpark, in a woodland, digging in the garden, etc.. Seems early 20th Century kids would be out there at an earlier age, certainly working class kids.