Static linking with LGPL is possible for proprietary software; the requirements are sometimes misunderstood:
If you statically link against an LGPLed library, you must also provide your application in an object (not necessarily source) format, so that a user has the opportunity to modify the library and relink the application.
The LGPL is great for software libraries written in C, but doesn't really work for any other programming language. It uses concepts like object files and linking that assumes C. Even in C++ which is closely related you get issues with templates (users can't easily replace that code by their own since it is inlined in the binaries)
Many programming languages don't even have the concept of dynamic linking or object files that can be shared.
So, relinkability is the key. For some platforms and toolchains that may be impractical but for others not so much.