Huh? If anything, in the good old days, there were WAY more kits than there are today. Besides that, hobby electronics has a long history of doing stuff like "Here's a schematic, here's a BOM, and here's a paragraph on the 'theory of operation' that assumes a solid understanding of electronics and a bunch of domain-specific stuff. Good luck!" -- Pretty much the same as it is today, except we have resources like http://electronics.stackexchange.com/ to answer our questions. Wish that stuff was around when I was younger.

Kits just save you the trouble of making your own PCBs and hunting down parts on Digikey.