Nothing against Plone (although I was very happy to put its foundation layer, Zope, in my rear view mirror). It's a fine program that's very good at what it does. But just because something's been around a while doesn't mean that it's still vibrant and growing.
Check out the charts from Google Trends some time.
Now it's probably the third option, when building websites... and a fourth option, when building APIs.
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I don't think Ruby is a fad. The drop off Ruby had since early 2010s is dramatic, but it stabilized around 5% of all PRs on GH in the last few years:
https://madnight.github.io/githut/#/pull_requests/2023/2
It's still one of the most popular languages for web development.
But is it? Stats on major job boards such as Indeed show a steep decline in recent years. There are consistently twice as many Django/Flask roles listed compared with Rails. Node is the most popular but Spring, ASP.Net and PHP occupy the next level below Node.
I extremely doubt that. Maybe in your geographical area with small stage startups.
At any given time Spring has probably seen 10x usage of RoR.
Python was all over the place when RoR came out, meanwhile I only remember hearing about Ruby on random forum posts or by some enthusiast before RoR.
Outside of this, it's been perl and python, with python replacing perl after that whole perl 6 fiasco while the language and distros started understanding packaging python.