Earlier quoted context omitted.
A book which stops you learning Ruby is in fact an excellent book.
I've been trying to figure out at which point ruby turned from hero into villain, but I feel like it's more a generation gap rather than some series of acute moments.
So you rush out and higher 10 react developers, 10 go developers, and 10 support engineers to try and write a micro service replacement while keeping the ruby app alive long enough to finish the rewrite. Oh and an elixir developer somehow managed to sneak in.
Meanwhile your original 2 Ruby developers moved on, and their replacements are treated like dirt since Ruby Is on the way out... for a few years.