Unfortunately, I think your memory is wrong. From a (quick) survey of http://perlmonks.com/?node_id=3989;BIT=reaped%20spam;Wi;M, the period of high spam was 2013 & 2014; which means the stats for those years are highly inflated.

Glad they are gone, but it make the overall decline worse.

As for 'deterioration':

Whilst quantity certainly isn't everything; and I agree that for the most part, the questions these days are better asked and answered; the interesting questions, good debates -- ie. learning opportunities for the more experienced among us -- are few and far between. And getting fewer.

And, whilst I have no statistics to back this up; my gut feel is that the turnover of actively contributing monk's is higher and growing.

Interesting questions occasionally draw out contributions from the more experienced monk's that attend regularly but don't often post. And those questions are usually the one's that have little or no direct Perl content.

If people felt more comfortable posting those types of questions; maybe it would draw them out more often.

And as the wealth of knowledge here is so deep; maybe that would attract more questions and more newbies to the site. If more people were visiting; then maybe they would also look at the Perl questions and be attracted to the language.

For me, the saddest part of the last few days, is the prevalence of belligerent complacency.