I actually blame the old guard for not putting in enough time and energy to mentor juniors. It didn't have to end up like this.
As for whether an SPA is harder or easier, that's not really the relevant dimension. You should not be making technology decisions for your company based on what your new junior devs are comfortable with. They will actually level up faster if they are forced to take what they've learned and apply it to something they weren't working on in their nine-week intensive.
Meanwhile, there's nothing "easy" about React and co when you factor in the layers of abstraction and bikeshedding involved in a typical full-stack deployment today. Compared to when I learned, you suddenly have to also be confident with bash, git, docker, AWS, postgres, webpack, and the whole concept of a virtual DOM before you even start modelling your data or thinking about state transformations. Now go compare that to the original Rails "blog in 15" video and you'll have a hard time claiming that anything is easier. The drop in developer ergonomics over this golden era of JS tooling is stunning in its unneccesary masochism.
> bash, git, docker, AWS, postgres, webpack, and the whole concept of a virtual DOM
That's very far fetched. A React app can just be the default template from CRA + some place to host the generated files (like Netlify if you want something simple). You don't need to know any of the above.
Sure, you can get an example of a React component working on a webpage. I'm talking about the daily lived experience of a working junior developer trying to build something real using typical tools for 2019.
I wouldn’t say it’s easier to build in these SPA frameworks nor harder. Attention to detail is something people recognize or learn over time.