The problem with the ARFs is that you do not get "attached" to them at all, hence you replace them very easily and go on to the next one very quickly. It doesn't happen with models you built yourself.
After 30 years of mostly building from plans, I purchased an ARF just for some sport flying and out of curiosity.
I bought a VMAR ESCAPE. It was good value for money, well built, and after 6 months and close to 80-85 flights I sold it to a fellow club member and at a very good price too. I sold it without blinking an eye. I would not have parted so easily from a scratchbuilt model.
I guess it filled its purpose and when I got "fed up" with it I just got rid of it.
I never got fed up with a model I built myself.
I decided that to have one ARF in the stable is OK, but would never convert to these models.
I don't even like the newer kits - they are like "Lego" in my opinion. I look for and purchase out-of-production kits when ever I can find one. Latest project was an Aeronca Champ from the Precedent kit, current one is the SIG 1/4 scale CW Cub, and next are the SIG Liberty Sport and old British Veron Tomtit bipe. I really enjoyed cutting the printed parts in the SIG kit, far more than "assembling" the ARF.
People in my club, especially the new commers, start with ARFs but get very interested in building a model themselves very soon. So maybe kits will not disappear, but I admit that when there's a kit I really like I buy it and store it in case in a few years I will not be able to find one. I dream of getting back to scratchbuilding, but do not have enough spare time right now.
What I would love to see is manufacturers re-introduce some old kits, e.g. the SIG Yak, Sterling Stearman, and such...probably will not happen.