Reporting bias favors extremes; by now, we should be seeing people crowing that they've MLB'd the eidolon with their 3 lucky Gatcha pulls. It could very well be that since the devs added a 4th copy into the PP pool, they drastically reduced the Gatcha pull rate. But even then, some people should be getting lucky.
As for myself, I got the SSR weapon as a drop from an Expert (started with my own AP). That's pretty rare in itself.