Photoshop/Lightroom are $100/yr combined (sometimes less if you can get a deal on the subscription card). At that price, you're still looking at significantly less than if you used to upgrade your old software every 5 years.
If you wanted both Photoshop and Lightroom, yes. For those of us that just used Lightroom, and could use GIMP for any light editing, it's a significant increase. I'm still using my perpetually licensed copy of Lightroom 6, and I see no reason to upgrade any time soon. (I'll probably use the Adobe DNG converter as a free translator if I ever get a new body)
I've used the website photopea as an alternative to Photoshop, I find it much more similar and convenient than GIMP.
Have you tried Darktable?
The new Dehaze and Texture sliders, plus improved highlight recovery are highly worth it. Also, the latest version is finally optimized and about 2-3x faster than all prior versions.
It's going to take more than some new features to make $100/yr worth it over $0/yr, but I see your point. I don't shoot as much as I used to; if I buy a new body at some point, I'll bite the bullet and do it.
Capture One is another alternative to Lightroom. I've since switched to that after Apple abandoning Aperture. I still vastly prefer Aperture's UI, but it's barely usable anymore after several years of OS updates.