@Stephen Cronin -

larger companies often have a culture of extensively testing each update.

Wait, are you saying that we shouldn't test software updates to mission critical systems now? Why wouldn't we test it? Is this what happens after a year of 1-click-update, that we start to forego testing?

They have dev, test and production servers and promote changes through these, following through an extensive test plan. Oh and they can’t just do this, they have to take the change to the Change Advisory Board for approval (which may take a couple of weeks), create the test plan, the roll back plan, let all the stakeholders know of the work and the potential outage, co-ordinate the update so there is zero chance of the site going down when something major is happening on the website, etc.

One of my clients has a legal requirement to have the share price on the front-page correct to under 15 minutes previous. Their website can not go down and cannot be akamai-type cached. Thorough testing of any update to any of their systems is not done because of their old-fashioned IT strategy, it's because without it, they are royally fornicated to the tune of millions of dollars.

And yeah, they need to do all this for a 1 click, 10 second update. So they love a stable product that doesn’t change much.

Um, no mention of training/support/documentation/translation the thousands of staff members on the UI and Workflow changes that WordPress pushes out every release. Obviously, that's just 1 click and 10 seconds to update too, right?

Thankfully a lot of these companies are realising that they need to change, but that’s the traditional enterprise IT mindset.

There's a very funny dicotimy going on with WordPress. On one hand we get upset when people say that WordPress doesn't tick the box for every solution; yet on the other hand we play the David and Goliath card when talking about Enterprise level IT systems. Pick one :)

Even clients who have embraced the business transformation required to move to agile development and deployment still need to actually test software before releasing it live.

EVERYONE should test each update for each of their sites.
Testing before you update the core of your Content Management System should be done by, surprisingly, you.

Why should Enterprise level clients be any different?