Anecdotally, I've experienced the exact opposite. The company I work with had been doing waterfall development for 15+ years. We switched to agile using the Scrum framework. It wasn't smooth sailing the entire way, there were teams early on that struggled with adopting Scrum. Most often it was due to the team attempting to solve every retro issue by updating "the process", which only addressed symptoms instead of fixing underlying communication problems within the team. The other major hurdle was getting product to accept that a roadmap isn't a set of commitments but is instead a list of prioritized "wants". Now, we're 3 years out from the switch and most of those pain points have been removed. It's lead to massive improvements in quality, predictability, and overall happiness across the company.
I had the same experience, in a longtime waterfall company, that adopted Scrum, with significant pain points but it was still a world of improvement. The thing that the Scrum haters don't see is that its biggest benefit is invisible -- it's in what doesn't happen, in what Scrum avoids.
Scrum avoids the eighteen-month waterfall death marches that kill a department or a company. Scrum gets you thinking in terms of managing scope, of pacing deliverables, of thinking of a list of prioritized "wants" as you say rather than a dictated set of commitments. Scrum makes you approach development as it has to actually happen in the real world, rather than as a dictated plan that inevitably won't survive contact with adversity.
Of course it's completely possible to still mess that up, with overzealous adherence to process and ceremony and metrics. It's very possible to run Scrum as a set of perpetual two-week waterfalls -- and very possible that that's still a great improvement over two-year waterfalls.
The problem with scrum discussion is it's always compared to waterfall, particularly unyielding waterfall. Even construction planning, which is where waterfall came from, of has slips and adjustments. There were other methodologies other than waterfall before agile or scrum arrived. I went to college in the mid 90s and they taught that waterfall existed but a more iterative approach was actually used in practice. If you were doing immutable waterfall, anything would have been better, maybe including nothing at all.
