I had the opposite experience. I had rented a house that had an empty patch of dirt and asked the landlord if we could plant some vegetables there (which I didn't have a lot of experience in). My older neighbor saw me and said that we had great soil in our neighborhood but I didn't really think about it. The vegetables grew amazingly well, we had way too many tomatoes and tons of broccoli that kept growing back and more. I barely took any care with it after planting, other than very sporadic watering and harvesting.
The next year we moved from that house to a new place, where we couldn't plant directly in the ground but the landlord was happy for us to use pots and planters. I eagerly planted my broccoli again thinking we'd have the same endless supply... but this time it barely produced anything and looked nothing like the last year. I bought some kind of soil bags from the gardening store after asking an employee which would be good for vegetable pots and planters. Something about the pots or the soil or otherwise made a gigantic difference even though we had moved probably less than a mile distance wise.
I'm a very amateur gardener so I may have made some other mistakes, but I think I treated the plants very similarly both years.
This makes sense as pots require very high precision of soil composition and water management. You need good drainage but a water reservoir under the pots with some kind of wick to keep it watering from the bottom. Also the size of the pot you need is huge compared to your intuition. A single tomato plant requires more than 100L of soil, 30% of which should be perlite, you need some pebbles for better drainage mixed in, and more than 50% should be compost. This often isn't enough for a tomato, so you need to add slow release fertilizers at different levels of soil. In a warm day (> 30C) you need to give 5L of water in the morning and in the evening. The water should stay in the pot but not flood it. Ah, also, they cannot handle cold as good as in soil either. So the pots should be moved indoors when it's too cold, and require shielding from a lot of wind.
If you prepare the pot, soil etc properly, you can get good results. It's very repeatable as it's a very precise recipe. If you put potting soil in a pot randomly it won't work at all.
I've had tomatoes grown successfully, with decent yield in pots that take maybe 30L of soil, and without any perlite. It isn't that hard if we're talking about hobbyist stuff, where results don't have to be ideal but just "good enough". Picking a variety that is hardy and forgiving, and a place with enough warmth and sunlight (at least in the North) is the most important part.
True. What I went for was extremely good yield, like 10-15kg per plant. That requires a lot of foilsge growth early on and proper pruning + a lot of water later on. Just good enough isn't that hard, though still the depth of yhe pot should be enough for root development.
A properly selected variety adapted to your climate needs both less soil, less water and and a lot less maintenance (still daily care but nothing crazy).
Yes, variety matters a lot. I've managed to grow tomatoes quite well in pots located outside in Northern European climate, simply by picking a traditional variety that is known to be easy to grow. (In Germany it's known as "Bonner Beste" if anyone is interested). It doesn't even require that much upkeep.
The next year we moved from that house to a new place, where we couldn't plant directly in the ground but the landlord was happy for us to use pots and planters. I eagerly planted my broccoli again thinking we'd have the same endless supply... but this time it barely produced anything and looked nothing like the last year. I bought some kind of soil bags from the gardening store after asking an employee which would be good for vegetable pots and planters. Something about the pots or the soil or otherwise made a gigantic difference even though we had moved probably less than a mile distance wise.
I'm a very amateur gardener so I may have made some other mistakes, but I think I treated the plants very similarly both years.