You get GAS from beans. The cure is don`t eat them.
If you feed the beast, you end up with a closet full of gear you can`t use. So you sell it at a loss and get sellers remorse or you keep it and build storage cabinets.
As far as 21 3.4, it was the worst Leica lens I ever owned. I sold it within 3 months and got a new pre ASPH 21 that just came out and I still have it. Think it cost $650.
All true wide angles vignette badly based on cosine 4th law. It does not clen up to f16.