However, incorporating this methodology into our workflow would be both a lot of work to set up and also a lot of work to keep running.
There certainly is a size threshold under which this is clearly an overkill and we are under that threshold.
Yet, if this could be turned into a product, a clean integration, a command I need to run... would definitely use it (and pay for it).
You should be upgrading all the time since day one, adding necessary infrastructure gradually as your app grows.
Conversely, I was called by a company that I had built an app for previously. They had not upgraded the framework it was built with (Laravel), and ended up offering me consulting days to jump several versions. The irony is that the job ended up being quick and easy to do.
Did you use a tool like Shift to help with the upgrade? What about frontend dependencies? The recent move from Mix to Vite is great, but if you have a large frontend, it can be a major PITA to update. More so if you have any sort of custom webpack configuration.
For example in many organizations partial deployments don't exist and rollback is not easy, so having a "once a quarter we test everything and bump" is less traumatic and expensive than handling minor breakages every week.
You can invest into that infrastructure/maturity but it may not be the best use of your time and money if you don't even know that your company will exist next year.
I think the pattern to consider is: (i) Yes, this would improve our deployment speed/upgrade speed/security posture, possibly by a huge amount. (ii) We have much bigger problems with higher impact.
Like, at work, we could spend a month or so to setup something like dependabot for our private stuff and I'm pretty sure we could get to a point of deploying these dependency updates quickly - or, for less critical systems, automatically even. And it would be cool.
But that won't help us with some of the flagship products in the company that have C++ dependencies on EOL windows components and no automated deployments. We'd rather have the capable guys working on these nasty issues, since these upgrades for the modern products can usually be done by a junior dev in a few days for all of these smaller and well-controlled systems.