And people ignore that Google could easily put some clauses on their contracts to force OEMs to upgrade, just like they have clauses obliging them to use Google Play Services if they want to use the store.
It is all a mater of what Google is willing to put on their Android contracts. No excuse.
Articles like this always seem to be some awkward attempt at turning a strength (Androids wide adoption, budget friendly alternative phones, etc) into a weakness, via the magic of nuance-free comparison.