I think an Ivy Bridge laptop would still be OK now with some upgrades. It would be hot and have bad battery life compared to Haswell, which was a big upgrade. I still think you would be crazy to spend 1000+ on such an old computer though.
TBH my next computer won't be an Apple laptop unless the next iteration is truly something special. They have gotten too expensive here in Japan.
As Apple started moving to SSD's, I believe they stopped caring about minimizing disk seeking when considering changes to their virtual memory implementation. I had a Macbook Pro with 16GB of RAM and a spinning-rust hard drive, and was constantly getting beachballs when switching between applications (I had FREE RAM and was getting beachballs!!!).
(Apple's ~2012 virtual memory behavior was a strange beast -- it appears it would page an application's memory out to disk so that it could hang on to some disk cache. This was different than what I had become used to in Linux, which always prioritizes application memory needs above disk cache).
Disabling the pagefile solved the beachballs, but with the downside that when I did run out of RAM, the machine basically ground to a halt. I later upgraded that machine to use an SSD, re-enabled the pagefile, and was back to smooth running.
Is bloat the problem? Possibly. More likely it was shifting priorities (minimizing pagefile access probably just wasn't a priority anymore).
But if that is true ( Which align with my own experience ) this would really annoy me. SSD or not, it should ALWAYS fill up the memory first.
If Apple's customers are not still seeing those big payoffs from new technology then it becomes a game of costs. Changing a product mix every few years has its own costs - as demand for new PCs drops, these costs become harder to justify for an OEM.
It is totally possible that a 5- or 10- year refresh cycle keeps engineering and support costs down enough to be worthwhile if consumers accept the technology meets their needs. New technology will still make it to the end user here, but Apple is not going to do it at any cost - they are masters of profitability.