...
According to that metric, ripple and dash are better than ethereum so I can safely say that can be disregarded as innacurate.
Ethereum developer community should include all the developers working on other startups which are building on ethereum.
Also, ethereum has the highest number of real world physical meetups after bitcoin which is a far better metric of developer support.
Vitalik is an advisor for Z cash, which he is free to do. And hopefully his role will allow him to draw knowlege from the development process of Z cash which can then be applied to Ethereum.
Ripple and Dash are better than Ethereum is what sense? In that they have better technology: No. In that they have a much more sustainable method to fund development: Yes.
I am not a fan at all of proprietary (ICO/IPO/premine etc) funding methods that tap the emission for development funding at all. For starters they leave the crypto currency wide open to regulatory non compliance as happened with Ripple and FinCEN. Nevertheless Dash's masternode voting development funding method, as flawed as it is, is way ahead of Ethereum's one time spinning diamonds approach to funding development. In the case of Dash the funding method is at least sustainable over a significant period of time while Ethereum's is not. Furthermore there is nowhere even close to the massive corporate overhead in Dash as there is in Ethereum, This shows in the CoinGrecko Developer rankings.
The only viable long term funding methods for crypto currency are Free Libre Open Source Software development methods that are based on a combination of in kind and monetary donations to software development. Monero is a very good example of what I mean.