Do projects get complicated? Yes, some of then. Mainly because most customers pay for features and not for refactoring or design, which they don't understand (remember, no in house technical staff). Try to sell them a new page with attached the price of a major refactoring... good luck with that. So sometimes features get kludged together because of budget constraints. I have projects with suboptimal UX (understatement) because they rationally decide to make tradeoffs between usability and costs. It's their privilege. I bet this would happen with any language or framework. Your customers could be more long sighted than mines, I hope they are.
So, would I move away from Ruby and from Rails? Yes, when customers won't like starting a project with Rails anymore. This means that other tools don't have to cost them more. Do I care about Rails architectural shortcomings? A little, but I appreciate its shortcuts more. They work well in my projects.