I don't disagree with your point, but one consideration is that GUIs are going to feel more familiar to most people, particularly non technically savvy people. Most people wont care about the objective efficiency of an interface - if it looks and feels like something they would use on their computer at home, they will feel more comfortable and adapt to it quicker. A TUI will be less familiar, more likely to be looked at as "old" and "clunky" (irrespective of its its merits) and thus people will adapt to it more slowly.
Obviously, "back in the day" TUIs were the only option, but computers were not as a prevalent back then, so there was no familiarity factor to leverage.
> Most people wont care about the objective efficiency of an interface
They do in the job roles I exampled because a large part of their job is quick entry. I have experience building and supporting systems for those types of users and a frequent comment is "I want to be able to enter information as quickly as I can so I can keep up with the customer speaking their instructions". Some of the older agents even preferred green screens because they could write with one hand and type with the other (while wearing a headset) -- I never quite got how they managed to multitask like that but kudos to them for pulling it off.
Back around 1999 I worked for a company and one of the jobs we had was to replace a financial data entry system which was written in BASIC and run on an aging mini comupter. Access to it was done via a terminal and it was a text based interface. The reason for replacing the system was part of the company's Y2K plan and in preperation for the Euro.
The company wanted everything to run under Windows so it had to be a native app with a GUI. When we deployed it there was a flood of compaints. Most of them were about the speed of data entry and the fact that the old keyboard shortcuts they were all used to had stopped working.
We tried to fix as many of the issues that we could but there was only so much that we could do. As it was a contract job we had to work with the UI the company wanted and as it was a contract job, once the bugs were fixed we couldn't make any other changes.
> Most people wont care about the objective efficiency of an interface
This raises another important consideration. A lot of software isn't and shouldn't be aimed at "most people". A few weeks spent learning something less intuitive can easily pay off over the course of a professional career using the software if it affords those that know the interface well a faster or otherwise better workflow.
Just a reminder so that you people don't design CAD software for heavy use by professionals in the same way you'd design a tax form for almost everyone to use once a year.
Obviously, "back in the day" TUIs were the only option, but computers were not as a prevalent back then, so there was no familiarity factor to leverage.