You have to be careful to separate supply and demand.
In the US the Fed regulates total nominal demand (= spending) in the economy. When the Fed is doing their job well, it doesn't matter for nominal spending whether any one industry, like restaurants, is disturbed or not. Or whether some industries are booming.
The Fed will just adjust how much money they are 'printing'.
But what matters are supply side factors.
All those people patronising restaurants or working there presumably did so because they preferred it to the alternative ways to spend their money or time.
After a disturbance, they will have to make do with their second (or third or fourth..) best opportunities instead.
If the disturbance was a long term shift in consumer taste, we should hasten the transition of workers out of that industry.
But the current crisis is presumably temporary. So we pay for lots of friction of adaption back and forth, just to get back to where we used to be. (The adaption is still a good idea. It's probably better for waiters to become eg Uber Eats drivers than to twiddle their thumbs.)