Now, let's say you look at the full catalog of commercial fonts. What's happening is a sort of acceleration of fashion. No sooner did the squared serif font come into style than it is on its way out. People are designing new fonts, other people are enjoying the new stuff, and the old stuff gets pushed out (not completely, ever, but enough that your average designer starts to really get annoyed seeing the same old fonts).
So this tool is probably a great thing--it should help boost the industry and it will also put more downforce on the value of the same old junk that has been around forever. So if you are really OK with standard fonts, or plan to use free fonts forever, there should be an increase in the amount of that stuff that is available for you to use.
This should also help commercial fonts take hold. People will start to notice fonts more, and they will start to understand the difference between the amount of work that goes into paid fonts vs. unpaid.
Fonts are not a solved problem by a long shot.
But expanding single styles into families is not as easy as it should be. That's why I help start http://metapolator.com which takes www.metaflop.com and removes the 'write metafont code' part of the process.
As you say, if you want the fonts to be better sooner than Google, you can pay for it - either by commissioning the designer to improve the open source fonts or by going across the street to a paid web font service.