Accessing Windows' NTFS volume from WSL2 Linux is (and will always be) even slower. I have no doubt they've could've substantially improved file access, but management pulled the plug. WSL1 was basically just a proof of concept, afterall.
Also, don't forget that Windows and NTFS has never been known for performance. Expecting file access to be as fast as ext4 from a Linux kernel was just the wrong set of expectations. If you want Linux performance you need to use Linux, of course, accessing it's own block device directly; and people demanding that are going to get it with WSL2. The cost is that integration will be worse, both in terms of ease of use as well as performance. AFAIU WSL2 is using 9P now and in the future probably virtio-fs (https://virtio-fs.gitlab.io/) or something similar.
People keep saying how lightweight the WSL2 VM is. Well, that's how all modern VM architectures are now. If you launch a vanilla Linux, FreeBSD, or OpenBSD kernel inside Linux KVM, FreeBSD bhyve, or OpenBSD VMM there's very little hardware emulation, if any[1]; they all have virtio drivers for block storage, network, balloon paging (equivalent of malloc/free), serial console, etc; for both host and guest modes.
[1] I don't think OpenBSD VMM supports any hardware emulation.
Also, don't forget that Windows and NTFS has never been known for performance. Expecting file access to be as fast as ext4 from a Linux kernel was just the wrong set of expectations. If you want Linux performance you need to use Linux, of course, accessing it's own block device directly; and people demanding that are going to get it with WSL2. The cost is that integration will be worse, both in terms of ease of use as well as performance. AFAIU WSL2 is using 9P now and in the future probably virtio-fs (https://virtio-fs.gitlab.io/) or something similar.
People keep saying how lightweight the WSL2 VM is. Well, that's how all modern VM architectures are now. If you launch a vanilla Linux, FreeBSD, or OpenBSD kernel inside Linux KVM, FreeBSD bhyve, or OpenBSD VMM there's very little hardware emulation, if any[1]; they all have virtio drivers for block storage, network, balloon paging (equivalent of malloc/free), serial console, etc; for both host and guest modes.
[1] I don't think OpenBSD VMM supports any hardware emulation.