No, I'm not trying to paint an overly simplistic picture. I'm going off of history. The stock market has been the sole focus of government for some time, over the concerns of normal people, jobs, the middle class, etc. Decades now.
That's truish. Or rather, it was true until 3 years ago. Reagan, Bush1, Clinton and Bush2 were all hard core supply side trickle down guys. Their focus was almost exclusively on the stock market. Obama doesn't really fall in line with that. By the end of Bush2's presidency, it was obvious that that approach had failed and today there aren't really many economists at all left still preaching supply side. The Republicans still want to keep going that direction, but the Democrats was to stop and roll back to a more balanced place.
One of several important indicators. Well give me the other "several" then!
Well, in my view, you have three big buckets that matter- supply, demand and participation. There are lots of indicators of the health of each of them and none is perfect. For supply, you have indicators like credit availability measures, the actual amount of capital going into expanding companies, new companies, production, etc. But, the stock market is the primary indicator of supply.
For demand there are also lots of indicators. Revenues, median income, exports, etc. But, the strongest indicator is consumer spending. Consumer spending is driven by the middle class, which is driven by median (not average) income.
For participation there are tons of measures as well. We could have a huge GDP, but it could do us almost no good if just a handful of people were able to take part in it. Measures of the distribution of wealth, people in poverty, etc, are all indicators of participation, but unemployment is the primary indicator at present. That isn't a great measure really. Theoretically, you could have a booming economy where only a small percentage worked and robots did the rest for example, so long as the proceeds were being spread around somehow, and you would have both high unemployment and high participation. Or, you could have low unemployment, but everybody could be working minimum wage jobs, and you would have low unemployment, but low participation. But, nonetheless, in the current climate unemployment is a pretty good indicator of participation.