I've noticed people's "computer literacy" varies dramatically based on the applicability of whatever they're trying to accomplish to their personal desires versus work.

Being a bit hyperbolic: An update moves one pixel out of place in a line-of-business application and helldesk calls roll in from core-dumping end users who simply can't fathom how to use the software anymore. OTOH, big streaming video or shopping service revamps their UI and the end users seem to have no trouble continuing to use company resources to play videos, shop, etc.

Edit: I have no doubt many large websites have better UX resources, as compared to LoB apps, but user motivation plays a big part.

Streaming sites and shopping carts are used by millions of people, but casually after work, maybe twice a day.

LoBs are used intensively for hours on end in a busy work day, and most people's livelihoods depend on them either directly or indirectly. You grow into them. Muscle memory used to be an actual UI design goal, back when TUI's were the most common LoB interface. Not so much anymore when everything is web app and you click through the horrid UI slowly with your mouse pointer, and repeat this identical task 200 times in a day.

edit: We naturally develop a muscle memory even for the worst LoB. But they are not designed with this in mind. If they were, they wouldn't move that one critical pixel around in a mouse driven app.