I think the actual percentage of Techs who drop out is much higher than 55%.
Last year, I sent out about 100 letters and many additional emails (if I could get an email address) to all hams listed as licensed in Accomack and Northampton Counties, Virginia, soliciting them to come to Eastern Shore Amateur Radio Club Field Day. As I searched the QRZ database, I found that many of the Techs' licenses had expired. So I of course did not mail to them, only to "active" licensees. About 40 of the snail mail letters came back, about 30 (out of 50 mailed to Techs) were Techs, or 60%. No signs of ham activity anywhere. Add that to the expired licenses. I'll do this again this year and be specific and scientific about it, but I think the percentage is more like 75%.
Why: (1) lack of interest in electronics or radio or ham radio as a means of emergency communication, and (2) not being embraced by a local club or elmer.
We can do something about #2.....
And maybe snag a few preppers (Baofeng got me into it, though I've gone way beyond that).
David, K2WPM