I work a 9-5 with a 40 minute commute each way. That 40 minutes includes 20 minutes of walking which lessens my need for other exercise. I get plenty of time with my 17-month old. 6-8 in the morning and 5:30-7:30 at night.
On the flip side, my wife works from home and loves her breaks when she can spend time with our child. She is also often lamenting a lack of time for exercise and social activities.
As for your wife, I may be misunderstanding if she works from home as a Mom or remotely, but my wife works from home as a stay-at-home-mom and exercises almost every day with two young ones. She takes long walks with the children, one in a stroller and the other in a front pack.
The other thing she does is a variety of workout videos. Our oldest actually does some of the workout with her and encourages her with the same phrases the people on the workout video use. (ex. "train your body!") It's cute.
Kids vary a lot in how much sleep they need. Sleeping 7:30pm to 6:00am is 10.5hr, while many 17-month olds need more like 12hr at night.
That said, imagine if you could do 40 minutes of walking with your child instead (or do the walk / ride / sport you wanted during that time), lose nothing, and still work the same hours?
Lamenting the lack of time for exercise and social activities is a problem of having children, not remote work. Working at an office, however, means you'll likely get first crack at that stuff because it's "on your way home" or "just a thing after work" but if you were working from home you could easily trade this time back and forth with your partner and they could do the same thing. That said, those interactions definitely require a bit more work than the social scene that's "built-in" at the office.
When I had an hour+ commute we ended up pushing our kid's bedtime to 11 which was nice to spend more time with him but then made it harder for me to get enough sleep! Now he is in school so 11pm bedtime obviously is too late.