No, it's not. Manual effort is being automated. That manual effort includes calling to remembrance a list of gems, looking up their installation instructions on GitHub, modifying views, editing initializers, converting ERB files to Haml, setting up your test environment just so, and whatever else floats your boat. Assuming a team can agree on some sensible defaults, it can save significant amounts of time to have all those steps automated each time you want to spin up a new project.
"The technical and social friction in changing the template discourages evolution."
No, it doesn't. There is nothing stopping me from deviating from the norm once the application is generated. Or if I need to preempt a step in the generator, I just 'gem unpack' the generator, make my tweak, 'rake install', and generate from that. If it works out, I can push the change up in a branch and submit a pull request. The team can discuss.
Automation is good. From a business perspective I believe it's codifying your expertise. Clients benefit from that automation, because you spend 10 minutes spinning up their project instead of 2-8 hours recreating pretty much the same wheel you created last month.