If you are at a place that sells an experience that happens to come with food that may be true, but one in the business of selling food is going to beat your home kitchen every time.

The big difference is that the home kitchen costs are largely front-loaded. This does mean you generally need less free cashflow when you are hungry, which is an appealing attribute to someone who budgets by looking at their bank account balance. However, it also means you sacrifice a fair amount of opportunity. That does not come cheap.

The economy of scale. A kitchen with professional staff and equipment making hundreds of plates do that far more efficiently than each person or family making their own food. The reason then why it is still more expensive to eat out is because of business burdens, such as parasitic rent and interest, parasitic taxes, and sometimes exaggerated profit demands from owners. And of course there are costs that are just nice to have, such as table service.

If you look how little healthy school lunches or lunches on ships cost, you see how efficient the economy of scale is in a kitchen environment. And truly, in many places in the world it is common for even the poorest labourers to eat out, because there is a balance without excess burdens taking away the advantage of the economy of scale.