Well, I have!
We actually did the test, with Anvil (https://anvil.works), which is explicitly a VB/Delphi-like platform for the web.
We took a straightforward CRUD-y consulting project as a spec, and built it with traditional tools and with Anvil. We did our best to keep it fair: We raced an expert against an expert, and we kept the web tech simple: simple templating, minimal JS, etc. And it was still about 7 times faster with the Delphi-like tool.
(It was actually 10x faster if you just count dev time, but we counted overhead meetings too - again, in an effort to be fair. It was still "one week" vs "one afternoon".)