Probably not. Please suggest to extension authors to dual-publish their extensions to OpenVSX and VSMarketplace. So far all authors I engaged with were happy do to so (except for Microsoft of course, who are the only benefactor of this wallet garden situation).
I also have an extension that I dual publish. I was surprised to see it’s getting as many downloads on OpenVSX as on the VSCode marketplace. I’m just glad it’s useful to more people for marginally no cost.
I think Cursor just mirrors the VSCode marketplace on their own servers. They used to have an ugly work around for installing extensions, but now it just works and I see links to https://marketplace.cursorapi.com/ inside of Cursor's extension browser.