Something is severely wrong when food service is more profitable than manufacturing and distribution and tertiary-degree stuff.
Waiting tables is a hard job, and not everyone can do it well. It's physically and mentally taxing, and to make money at it you have to be charming which is harder to train than, say, packing boxes in a warehouse.
Good-paying waiter jobs tend to be in high-cost cities, so you'll spend more money on housing, transit, and food than a worker in a suburban warehouse. Waiters are also harder to substitute for - due to the small scale and personal nature of restaurant service, it's unlikely a restaurant could drastically improve waiter productivity without impacting the customer experience.
Also, to your point in comparing the hourly rate: warehouse and office jobs offer a different type of financial value to workers - relatively predictable schedules. If you're a student, working a few evenings a week and raking in tips is great. If you're trying to support a family, getting consistent full time hours may be more appealing than a higher hourly wage with lower/less consistent hours.
Maybe not everyone can do it, but once I got laid off from my 4th or 5th IT sales job in 6 years, I said to myself, "self, it's time to find something more stable".
The very first people to offer me a shot were a very busy italian restaurant, and everything is going amazingly well considering when I started, I didn't know how to make an espresso or hold 3 plates!
Still, it is really shocking to me that so many of my colleagues are in the same boat: Reputable college degree, no stable office job.
Our customers are all mostly old/retired couples. We appreciate their patronage heavily, but we greatly wonder why their money is being spent on food and entertainment rather than high tech skills.
This forces us to specialize in skills that will never deliver a 10x leap in innovation. The market for food service is saturated and we will never make enough to jump to the upper class.
That's the flipside of it being more stable. To make a jump, you need something that's higher variance, which IT sales certainly is.