Going back a couple hundred years, ~80% of the population was a "farmer". But by any standard, they had "multiple jobs".
I.E., they were doing a lot more than just growing food to sell.
You probably had a sweet spot somewhere between the 20s and 60s where you didn't yet have mega farms, but also <20% of the population was a "farmer" - so you could actually make a living off that.
Now, most of those farms have been sold off to mega farms or handed off to kids that don't really want to be a "farmer".
With the mega farms came efficiency, and if you're trying to be an inefficient small farmer, you're going to have a bad time competing. Hence, the need for a second job.
Anyone under 30 trying to compete with a mega farm is like some solo developer trying to build the next Google.
It's never going to happen.
Either you're doing it as a "hobby", or you REALLY want to farm.