Under Reagan and Bush (who both raised taxes AND spending) the national deficit was the bears big argument of the day. It's all I ever heard about back then.
Interest rates were finally lowered about the time of the Gulf War (in which we kicked #$%$ quickly-yeah U.S.A.) and before bears knew what hit them, we were in the greatest time of peace and prosperity ever.
Not saying it will definitely happen again, just saying it could and hope it does.
In 1999 and 2007 the market reached new all time highs 1580 and 1590 respectively. The people calling to sell were openly mocked and laughed at on television in public. Unemployment was near its lowest, the economy was expanding and the calls for s&p 2000 were rampant. Unfortunately the buyers or holders at these levels have yet to make a gain in the 6-14 years since. History is littered with the tombstones of buyers/holders at this level.
And btw, eveyone agrees with YOU though. Look at the vix, near historical lows. You might think there are alot of bears out there but there are not. Only on paper. In the real market there are nothing but greed crazed bulls.
I'm not kidding man I think the SPY will be over 1000 in a few years. Having said that, SPY has less than tripled in 18 years. If you add in dividends, it has not even doubled twice. We need to make up for lost time now and really go to the moon.
The one caveat is we seem to have entered a new era of booms and busts with epic crashes every few years. It certainly could happen again and if it did, things are so leveraged that the Dow could drop 90% in a year. It's not likely though, far more likely is Dow to 1 million in 15 year or so.