I have a mixed reaction here, and I suppose it depends on the agreement/expectations (implicit or explicit) that someone building a site - based on WordPress - has when they start.

I certainly don't like the idea of code changing under my feet, which might very well break something. (If they ever force auto-update when a site is only a point revision behind... then we'll have words!) But, I also don't think there should be a website/CMS out there that isn't being properly maintained.

Unfortunately, the reality (in my experience) is that a lot of websites on the 'Net aren't being properly maintained. And, that sad state of affairs is primarily due to how websites have been 'sold' to end clients for so long. You know.... '$995 and you too can be the proud owner of a website.'

The expectation of ongoing support or expertise needed to keep a CMS or any web-entity actually functioning and even remotely up-to-date with current technology was never part of the deal to begin with.

I suppose most basic WordPress sites would take updates like this without too much trouble. And, more advanced or custom sites (most likely to break) are also more likely to be maintained.

In my opinion, there shouldn't be support for versions beyond a certain reasonable age (and 4 years is crazy gracious!)... but the problem is that it's hard to just let them sit there out of date as well. I almost wish if they got too far out of date, they'd just auto-shut down.... like a web & user-safety kill-switch or something.