I do wear an anorak for ski tours when it is very cold and dry, but otherwise I sweat too much.

I do wear alpha fleece under my rain jacket at night, in camp, once it gets cooler. As you probably know, Alpha fleece originally got sandwiched between nylon in a jacket form. I think the way hikers use is more versatile (with or without a windshirt.) I am not just as enamored with Alpha fleece for my use. Again, if I hiked more open trails, did not sweat as much, or even more gentle with my gear, it’d be a viable option for me.

I suspect there will be a different latest and greatest garment in a few years and the cylce will repeat.

Lined windshirts (light fleece with a nylon windreakers) were the rage 20 yrs ago for thru-hikers. They are still around as a niche item as one example the comes to mind.
https://www.marmot.com/men/jackets-and-vests/fleece/mens-pinnacle-driclime-hoody/AFS_195115259488.html

We’ll see what’s next.

Yeah, that makes sense. I’ve found Alpha fleece to be an incredibly lightweight midlayer, particularly for cold-weather hiking or skiing. Its breathability and ability to manage moisture really shine in those conditions, especially when you’re working hard but need to avoid overheating.

I’m surprised to see people wearing it on its own.

What I wrote in the article concerning windshirts –
I am not as enamored with Alpha fleece for my hiking style. Wind shirts make me too warm, and the Alpha fleece, by itself, is too delicate for the hiking I often do on the Colorado Plateau.
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Many people will pair the Alpha fleece with a wind shell for versatility and light bushwhacking, but you add more weight, add a futz factor, and reduce the breathability.
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You can pair it with a windshirt for more abrasion and wind resistance, but add weight and mitigate the breathability aspects.

It might be worth trying it out with a shell to see how it performs for you.