Warren in Lancaster, PA
I think the problem with the double iron plane has been arrogance. People who were beginners have insisted that they were experts. Some have insisted that they knew more about planes than 18th century cabinetmakers.

I would give David Weaver credit for being open to the idea that he might learn something by experimenting some more. Here is the exchange that signalled the start of the forum's present interest in double irons.

http://www.woodcentral.com/woodworking/forum/handtools.pl/page/9/md/read/id/446436/sbj/warren-an-update-on-double-irons/

and
http://www.woodcentral.com/woodworking/forum/handtools.pl/page/7/md/read/id/447020/sbj/what-is-a-double-iron/

Here is an exchange from just 5 months ago:

http://www.woodcentral.com/woodworking/forum/handtools.pl/page/24/md/read/id/443879/sbj/difficult-woods/
And one from 2007

http://www.woodcentral.com/woodworking/forum/archives_handtools.pl/bid/3107/pro/search/pmd/sread/srchid/6032hEjqaujq3xj624q1337880673/spage/1/sanc/117565/sbid/3107/md/read/id/117564/sbj/i-don-t-think-so/

The archives have recently gotten harder to access.