There is a huge range of output/resource ratios for home gardens...even for home gardeners who say they're trying to achieve a high ratio. (Vs. love puttering with a garden, or want small quantities of perfect-in-their-eyes baby vegetables for salads, or ...).

Note that for many modern folks, "regularly gets you outside and exercising a bit and perhaps interacting with neighbors" is a valuable output. And you should also consider the vast processing, handling, & transportation wastes (including your or a delivery driver's time at the wheel) of the alternative.