[Klaus]

I reckon that this lens will put some pressure on the other manufacturers (although much of the credit goes to Panasonic's 20-60mm).
However, a high-performance zoom lens in this range is surely difficult - especially while keeping things small and lightweight.
I doubt that Sigma and Tamron have the design capabilities. Canon, yes (at sky-high prices). Nikon, not sure. Fujifilm - no.