As a decrepit old {COMMO} power user, anything that doesn’t give me fully integrated scripting with expect/switch/dialog and a popup script editor, honestly hasn’t been worth investing in further. So I’ve been on Linux console, Putty, and macOS Terminal ever since.

My terminal.app color scheme uses P3 colors on 7% gray rather than the usual sRGB colors so that I can use an OKLCH equidistant palette, and I make extensive use of shift-cmd-up to select and copy “the previous command’s output”. I considered switching for 24-bit color but ultimately I prefer not having to learn a new “rudimentary” app that’s deficient versus my nostalgia just like all the others, and it drastically reduces my stress level when working on other people’s devices that I am proficient in working with an OEM environment.

I occasionally use tabs but for the most part I prefer windows, so that I can drag them around and over/underlapped with other work I’m doing in my GUI. Not a big fan of screen and tmux except as their limited value to me in mitigating ssh disconnects when that’s a concern.

Perhaps your definition of power user is limited to uses aligned with your own?

It's what I've used for years and it's entirely fine for me.

For a long time I installed iterm2 because "that's what you do" but one day I realized I was suffering a little wasted disk space, slightly slower start-up, and slightly worse input latency, for... no reason, because I didn't do anything with it that Terminal.app couldn't do.

25 years on unixy operating systems. Spend tons of time in the terminal.

I used IE back in the 00s (up until Chrome came out), and I certainly was a power user. I liked it just fine. I think that it's a matter of personal preference rather than something sucking (or not).