I want to give some input on this.
There are basically 3 different counts for the DOW and S&P500 each.
They are pointing to different years for a crash to occur.

1. count says a big (at least 50%) crash will happen within 6 months
2. count says a big (at least 50%) crash will happen in two years.
3. count says a big (at least 50%) crash will happen in 10-12 years.

It is either or and for now, we cannot see a clear favorite count. It can happen anytime now, that is the dangerous part of the late-cycle.
Brexit, EU-disintegration, USD losing reserve currency status or any war escalation could trigger the crash.

BUT: I think they are going to desperately print money (and even use helicopter money and central banks buying 50% of all stocks...) until even printing money is not gonna push the stock market higher anymore. So I slightly favor the crash in 10-12 years. But who knows...