No, clearly not. I've been following the Ethereum proposal from early stages and was moderator pro-tempore on Ethereum through the public beta until we recently graduated to a full site.
And there were all these people rolling eyes, and telling us Ethereum questions are well on topic for Bitcoin Stack Exchange. At some point, Bitcoin even reconsidered to change the scope to Blockchain or Cryptocurrencies to be more inclusive. But they never did.
And here is why: Because Stack Exchange sites only work out for certain technologies with dedicated communities. Ethereum introduced a full stack of new programming languages and even a new programming paradigm. It quickly gathered developers from all over the world curious to learn the new concept and the site was one of the most active communities during an early public beta, with up to 100 posts per day.
Now, imagine, there is a site in the network called Bitcoin, or even Blockchain, and 90% of the questions are about Ethereum. What would you do? First of all, most of the users would feel misplaced, repeatedly asking highly specific questions on a site not really dedicated to the topic, they are not programming blockchain or touching Bitcoin at all. It's an absolute natural move to create something clearly dedicated to the topic. Similar to Ubuntu having it's own site even though there is a Linux Stack Exchange.
And Area51 is the perfect place to test whether a new community is worth to have it's own site in the network. The process of proposal, definition, commitment, private beta, public beta, and final graduation is nothing I would describe as something that's approved at moment's notice. It's long, winding, and stony road. And every community deserves a chance to test the waters. Who remembers all skeptics that said Ethereum will fail in private beta?
Good luck IOTA, which is -by the way- neither a cryptocurrency, nor really a blockchain.