Subject: Why don't many people build RC airplane kits anymore?
The answer is quite simple. Life has gotten more complex with people spending greater hours at work, working extended days, commuting extended miles, and etc. ARF's have come down in price, where to build costs more than to purchase, install equipment, fly. Gone are the days where one left the office or workplace promptly and was at home in 20 minutes or less.
Alternate building materials such as construction insulation 0.25 in. (6mm) thick foam and corrugated signage material have lead to a plethora of designs quick and easy to build, that are low cost, durable, and easy to replicate. Electric motors have simplified installation, even usage of double stick tape to fasten Velcro removal systems for batteries, receivers, servos mounted near control systems have made standard kit construction techniques obsolete. Drop in battery prices allows one to take with them a half dozen extra batteries, with extended flight times to match those of nitro fueled aircraft. Those into slow duration flying can chop the throttle completely in a gentle updraft and soar those Texaco-like aircraft in a summer thermal.
Those who used to bring out a .40 to .65 nitro powered aircraft now are showing up at the field with one or more .20 sized ARF electric warbirds, still having the same fun as with the nitro planes.
Due to ARF's, a remaining faithful in the kit building genre following have lead to cottage industries making short and long kits of legacy aircraft, to satisfy those building kits. If manufacturers would explore some of these alternative construction materials with ability to bring down kit prices may see a following still in kit building.