Yeah, I've had this happen to me. I wrote a directory in cakephp and neglected to update it. Eventually the ROI to me of updating it wasn't worth the hassle.
The one exception is if you outsource the stack updating. For example, https://letterstoanewdeveloper.com/ runs on wordpress.com. In this case, I don't have to worry about stackrot, I just have to pay the bill. If/when the bill becomes too much, then I'll convert it to HTML and host it somewhere. (And yes, if I'd done it as HTML first, I wouldn't have to make the effort.)
The one exception is if you outsource the stack updating. For example, https://letterstoanewdeveloper.com/ runs on wordpress.com. In this case, I don't have to worry about stackrot, I just have to pay the bill. If/when the bill becomes too much, then I'll convert it to HTML and host it somewhere. (And yes, if I'd done it as HTML first, I wouldn't have to make the effort.)