Why the NYA and others are rangebound for almost 2 years at a stretch? Is this a replica of the 1970s?

The NYA was making new highs until May. Ditto the Dow. The SPX has been ranging since then. The Naz is doing just fine.

Ain't summer wunnerful?

Seems like 2015 (and other years ending with a "5") are gradually getting converted into years of re-accumulation.

It's possible. But then this market is eight years old.

On the other hand, this is hardly the longest bull market we've had. The big problem is the rate of acceleration over the past two years. Which may help to account for the multi-month sluggishness.

Unjustified behavior of the stock market from mid 60's to mid 70's

Attached is the chart of interest rates (the red line). As it is evident from the chart that the interest rates made irregular high peaks after 1965/66 and as a result the stock market halted for that decade.

Again the interest rates reached a peak in mid 70's and market halted again.

So one can infer that irregular spikes of the interest rates was definitely a cause for the unjustified behavior of the stock market from mid 60's to mid 70's. But, is that the only reason? Were there other factors? Kindly mention them.