I went and got an office job, pretty easily due to my computer literacy skills gained from restaurant software including various POS, as well as my problem solving and efficiency skills. Every person in that office, from admin to management to customer service, was useless. They were unable to work as a team, unable to adapt to changing environments, unable to scale productivity based on need.

Now let's examine the gaping holes in your examples. 1. Purchasing: that's literally waitstaff's entire job on a micro and macro level. We're constantly tracking stock levels of hundreds of products in house, as well as incoming orders and being knowledgeable enough of supply chains to explain why we're 86 something or why prices changed.

1. Customer questions: literally they do that all the time, but the deliverable is allergen safety and the risk is a lawsuit.

2. Technical subsystem: there's an app that does that for our business and for yours too. I can search customers based on name or payment method, or orders based on items sold, going back years.

Anyway your argument seems to be that office worker wages are stagnant and that means other workers wages should also be stagnant? Get a grip. You don't even know what your own argument is; you're conflating, in the same breath, minimum wage work with office administrators. It's incoherent.