> Interest in the ecosystem is shrinking and this is one symptom.
I think the interest in the ecosystem is still very strong, there is just more publicity and marketing around the newest frameworks and capturing peoples attention. Rails is more than ever the best place to go zero to one, and still scaling past 100M at GitHub.
There are so many libraries that are largely feature complete. For example, Devise doesn't need anymore features. There is some traction of going the more lazaronixon/authentication-zero route which is a generator for owning the code rather than having everything live in a gem. This is just one specific example. Rails is moving more and more third party things in house showing it matured in the ecosystem and can move into core Rails.
I find myself reaching to a gem as a last resort if at all possible these days.