That anger was the result of people misunderstanding a marketing exercise by Adobe. Basically, in some markets the $9.99 plan was "hidden", so some potential new subscribers only saw the existing $19.99 plan, and that was misinterpreted as a "doubling in price", which wasn't really the case.
In any event, that marketing exercise has been halted, and I believe the "normal" plans are once again available in all markets. There has been no word or other indication from Adobe about a price increase....though speaking personally, I thought the original subscription price was a "steal" 5 years ago, and the fact that it hasn't increased since has made it even more of a bargain in my eyes. If Adobe do increase the current subscription costs at some point, I'd find it difficult to argue against provided it was reasonable.
Also that test had nothing to do with the apps. It was about cloud storage. Abode wanted to see how many people would click on the 1TB plan that day.
After about 5 years the Singe and All Apps plans went up 6% last year. That would equate to about 60 cents a month for LR. I'm assuming an increase will come some day and as long as it is reasonable it won't bother me either.