Maybe in your experience. personally, I've not found it to be too frustrating to maintain a side hobby/business doing and selling woodworking items.
Potentially, if you view "full time" as being 10+ hours/day, then yeah, it would be hard, but, if you can manage 8/day on work +2 per day for commute/errands and 1 for relaxing, you still have 13 hours left. I like to sleep 8 hours/day, so, 5 total that can be allocated to hobbies/side projects. even if you lose 2 more hours to inefficiencies/task switching losses, then you still can spend 3 hours on the project, and if you do that with dedication it works pretty well.
I take it you don't have a family? Because I don't see any time carved out for spending quality time with a partner and kids (if you had one or more).
I'm not entirely sure why the person you replied to got down-voted so heavily. Yes, it's possible to do stuff on the side, but it is exhausting and hard, especially if you are juggling a full-time job and family life.
As a husband and dad to two, there is a lot less free time available on any given day to pursue side projects and hobbies. I prioritize time with my family, and I prioritize time to take care of my health (work out), and that leaves very little time to devote to hobbies. Even with an understanding spouse who is okay with me spending my nights after the kids go to bed on study/hobbies, I get 1-2 hours on weeknights at best. I still build things, learn things and tackle new things, but it is hard, and it can be very exhausting if you try to sustain it over long periods of time.
But I like my job, my co-workers, and I like where I am at life, so I have no complaints. If I wanted to switch careers or build something substantial on the side, I would definitely recommend doing what the OP suggested, even though it seems riskier and harder.
I have a wife, no kids. My wife and I will go to the gym together, eat dinner together, and spend time together, but her work and mine have different schedules so I am done much earlier than her each day. (I usually start at 5-6am and finish at 2-3 since I am in CA, but work mostly with ET and IST)
Do you cook for yourself? Cooking is one of my biggest time sinks. It takes me like 45 minutes to whip up some eggs and pack a lunch for the morning. Dinner is around double that between cooking the dish, eating it, and cleaning.
What is your commute like? I can bike to work in 15 mins but now its too cold and icy for that, and it takes 45 minutes to drive through rush hour and park (and I'm bent over with the parking pass situation near work). Lately, I've been using the bus, which is hundreds of dollars cheaper than maintaining the parking pass, but no faster. Somehow, I live only 1.5 miles away.
Yes, I cook for myself, and for my wife. I don’t have a commute (or more properly, I work from home, or fly somewhere to do on site work with clients). My wife does commute so I do all our cooking.
I keep the time down with a combo of simple meals, batch prep, and Costco.
Have you considered meal prep? The majority of cooking work is duplicated across meals so if you can batch it up on the weekend it saves a lot of time during the week.
This works well if you are in your early 20s or otherwise have no real obligations, but otherwise it becomes very untenable unless you are ruthless about carving out that time, and the other people in your life are accepting of that prioritization.
The best I can do is try to carve out a couple of hours late at night or early in the morning, when everyone else is asleep. But you end up robbing Peter (sleep, chores, exercise, cooking, time with loved ones) to pay Paul.
Potentially, if you view "full time" as being 10+ hours/day, then yeah, it would be hard, but, if you can manage 8/day on work +2 per day for commute/errands and 1 for relaxing, you still have 13 hours left. I like to sleep 8 hours/day, so, 5 total that can be allocated to hobbies/side projects. even if you lose 2 more hours to inefficiencies/task switching losses, then you still can spend 3 hours on the project, and if you do that with dedication it works pretty well.