We're a society that depends heavily on the service sector. Over 3/4 of the GDP comes from services. And over 3/4 of the people depend in one way or another on them for their job.
Services are awesome when it comes to generation of GDP. Because it's pretty hard to store them. They have to be used when produced. More, they usually have to be consumed. And only by consumption, value is generated. Yes, consumption. Not production. That's hard for the supply side preachers to wrap their head around, but tell me, what did you create when you produce something? Revenue? No. You accrued cost. You had to invest material and manpower to produce something. Without having someone to sell it to, it's quite worthless.
Value is generated when you sell it. But that doesn't contribute to the GDP yet. Because if whoever purchased your good or service uses it to produce other goods and services, the value of your product becomes part of the cost for his product. That's, globally speaking, a zero sum game. The 100 bucks you just earned might have gone into your pocket, but the economy, the supply side, did not generate anything at all yet. Because some other supplier is now 100 bucks short and needs to find an end customer, a consumer, that not only pays those 100 bucks on top of whatever he has to ask for to cover the other costs he has for material usage and his manpower.
Only when someone buys such a good or service and removes it from existence by consumption, actual revenue is generated. That, or when you export it.
Now, as stated in the entrance sentence, we're pretty dependent on the service sector. And it's damn hard to export services. How do you sell a haircut to some Frenchman? Only if he comes to you as a tourist. And ... well, let's say the US didn't really make themselves very attractive as a tourism destination lately.
If you want to sell services, you need people with money. And most services are simply bought and paid for (and consumed) by average people. For a simple, logical reason: I only need one haircut. No matter how rich I may be. I only need one gardener to cut my grass and I only need one house cleaning service to clean up my mess. I won't hire another one.
Services, though, are something you need to be able to afford, and they're usually also the first thing people cut back on when money gets tight. When facing the decision between having something to eat for the rest of the week or getting a haircut, I guess it's easy to determine which one it's going to be.
In a nutshell, and the TL;DR version: If you want jobs, make sure people have money to spend. It works pretty well for countries that didn't axe their social programs and ensured that there would be many people who can still spend money on more than just food&shelter.