WordPress’s ridiculous obsession with backwards compatibility and insistence on continuing to support PHP 5.2 is the cause of all this (security support for 5.6 ends in December for goodness sake, as it does for 7.0). 7.2 is now the minimum recommended version, but it’s just that, a recommendation.
I was quietly hoping the minor furore surrounding Gutenberg might force a “soft fork” of WP - version 5.0 would embrace modern PHP/JS development with a requirement of at least version 7.2 while WP 4.9 would receive maintenance, security updates only (good blog post about that here). I don’t see it happening though.
Personally, I’ve gone all-in on 7.2 (I even removed 5.6, 7.0 and 7.1 from my production server yesterday). I’m the benevolent dictator of my servers - if a client’s site requires a plugin that doesn’t function properly with 7.2, I’ll find them one that does.
@mrmad/@fbsena - I switched to using The SEO Framework a while ago - simpler and just as effective.