As a M$ Windows user for years, I can tell you there's little to no incentive in Linux development. That's why M$ Windows is so much better than Linux, they give incentives / rebates to hardware manufacturers if they can sell pre-installed Windows PCs/Laptops. So they are willing to build device drivers to support Windows.

I don't get it why you have to blame Samba devs? SMB protocol was built by M$. It's not easy to build something like Samba, at least they need to analyze how the SMB protocol works. If you want a better compatibility for sharing data with SMB you should use M$ Windows.