I could keep using PS CS6 and LR6 "forever", and those tools don't change without my approval.
Well L6 is already broken. The map module's licence from Google has expired, so it doesn't work without significant hacks.
You're also at the mercy of Adobe continuing to authenticate the software via their activation servers if you ever need to re-install assuming it continues to work on newer OSs.
(In fairness they made CS3 available in perpetuity when the decided to turn off those activation servers)
If there were a model whereby after, say, a year of paying the subscription you could stop paying and would be stuck on the last version you downloaded, I'd be all over it. Ironically, I'd likely then keep paying them £120 per year for the upgrades; but safe in the knowledge I wouldn't lose all access to the tools if they suddenly decided to change the terms or significantly increase the price.
As I understand it, if you stop subscribing the only thing you loose is the ability to use the develop module and the map module.
All the other modules continue to work, so you don't loose access to you original files, you can import new files to the library and can export and print 'developed' images. I'd assume you won't be able to import file formats that the last subscribed version didn't support, but you could import JPGs, TIFFs and raws from supported cameras (even if you couldn't edit them in the dev module*) etc.
I think that very fair and reassuring in the long term.
*Whether cutting and pasting XMP data could work for new basic edits would be an interesting experiment. As that worked for adding some unsupported options to LR6
So far Adobe have played very fair with subscription. They haven't put their prices up and have continued to innovate and deliver great new features.
I think there will be price changes soon judging by the market research they've been doing, but I'm not unduly concerned it will be terrible for my usage.
If you think Adobe are not to be trusted and a worry, go look at what Phase One have been doing to Capture One. They've been an absolute car crash of price gouging, changing direction and failing to innovate. C1 used to be my regular alternative raw convertor, but I've not fired it up for three years now.