I have switched over to MAJOR food production in the past decade, versus landscaping and perennial gardens. Some from necessity, but more so now that I have more room and a willing partner to help me who also believes in self-sufficiency. I have everything I need now, over years of buying things a few at a time (tiller, tools, quality hoses, unheated greenhouse) first and second-hand and learning a lot of ‘hacks’ along the way to make life in the garden easier.
I also know exactly what will work for me in my growing zone (5a) so I don’t try to baby anything else along. Between eating seasonally, canning and preserving, hunting & fishing we could hold out longer than most when it all goes south.
Personally? I think you get the most bang for your buck from fruit trees, small fruits, tomatoes, green beans, peppers, potatoes, basic herbs and squash of all kinds; summer and winter keeping.
This season I’m adding plants for a Tea Garden. Nothing fancy, just a few additional pots and plants tucked in, wherever. Adding blueberries because we don’t have them, but we already have strawberries, raspberries and grapes. Plenty of wild Black Cap Raspberries to harvest, as well as Elderberry blossoms (tea) and berries - though the wild birds usually get to them first. We have Morel and Golden Oyster mushrooms in season in our woods; not much nutrition, but a FREE seasonal treat! :)
Your mileage may vary, but I think if you’re serious about it, have the time, are a willing participant (how many of us as kids were FORCED to hand-weed or hoe the garden?) and you’re past that learning curve and initial cash layout for bigger items, then, yes. It will eventually save you money.
That said, I also support two favorite local small farms/enterprises by buying direct on some fruits and veggies. Everyone wins when you do that. :)
I think that most people will break NOT break even growing a garden. A garden may be a satisfying hobby today but which might become a necessity in the future. (Or, if not necessity, provide some relief from rising food costs and possibly, better food quality.)
People might consider beginning gardening now for the sake of experience. It can have a steep initial learning curve. Better not to wait until there is a food emergency to learn. The more you know the sooner you can move from the hobby side to production, reliance, and maybe break even on your investment.
The other reason is that there is preparation and lead time involved in gardening.
Bare Bones; Start with a fence; A gardener needs a fenced in area unless you live on an island that has no dogs, rabbits or deer. First year, turn the soil, prepare and plant your garden. Second year; you have already tilled your soil (Or piled books of straw on your no till plot!) gardening will be easier and require less work.
(Also, after the first year you should know if there was enough sun to support continued gardening in your selected plot.)