After the massive breakup, first generation ITF instructors(ones directly taught and trained by General Choi) went independent or had another ITF organization led by Nam Tae Hee, the former #2 man in ITF, but the power and the glory of the ITF eventually faded away. WTF literally trouncing in the limelight, gained momentum and filled the void left by ITF as the  official governing body of TKD . WTF created Olympic rules for TKD and offered WTF certificates to former ITF instructors. Some refused, some joined.  WTF announces the  acceptance  of  the  former ITF instructors including famous ones such as  grandmaster Cho, Hee IL into WTF. Few more ITF instructors are inducted to WTF, because according to some, there was no other choice in order to train and send their students to the Olympics. But the process is a hard sell, some former ITF instructors have refused it for over 15-20 years lamenting the  purity of the true TKD will be lost for the sake of sport. Ironically, same argument was given by the Judo instructors in Japan when Judo was accepted into the Olympics. and lost the martial arts aspect of Judo.

Other ITF  instructors created their own styles sometimes reverting to or adding their old school techniques. Some former instructors mixed both the ITF/WTF styles doing ITF forms and WTF sparring to those who wanted it.

The first generation ITF instructors overseas who left the organization were helped by their colleagues in the U. S. to set up dojangs. Some went to teaching full military style initially to the public(since there were no more
control by a central authority to observe or impose regulations). These schools lost many students with rigorous curriculum of TKD designed for actual battlefield fighting(eg. you passed your level of belt when you beat your sparring opponent who is also testing, and sparring was done without protective gears in the military). Lower ranking color belts when taught battlefield techniques, a common practice in the military, started applying the dangerous techniques without caution or left with fully bloated confidence.  It was a
hard sell.

What the public wanted was a quick-fix comfortable learning without much emphasis in excellence.  The hard style training began toning down to less rigorous and non-regimented style to pay the bills, increase and maintain the number of students business wise, and to avoid lawsuits of physical injury. It was the beginning roots of watered down TKD.  As WTF began to dominate the TKD, it was a bigger challenge to the former ITF schools to continue.  Some ITF instructors eventually opted for the  WTF conversion offers to get their schools going as the  real (their quotes) TKD school.

Highly skilled and/or business savvy former ITF TKD instructors went a step further in being independent realizing that they could do what Gen. Choi did with TKD. They researched, modified, and created a new style of their own autonomous TKD organizations. These savvy first generation ITF instructors in this group flourished. 

Eventually after the decline of the formidable ITF organization, a strong unified body of reference for governing ITF techniques was no longer existent. Some eager for money and/or less skilled students of first generation ITF instructors splintered into numerous groups of any permutation involving the following combinations; contact or non-contact sparring, elimination of 3 step sparring, different ways of interpreting movements, modifications of movements, sloppy forms/patterns & moves, stricter forms/patterns, new forms/pattern, no
protective gear fighting, full padded gear, light gear, mediocre teaching, increased belt levels, unorganized curriculum,  etc. The  complete martial art now became fragmented, splintered, and diluted.

The teaching system was fraught with instructors moving on and teaching with only partial knowledge of the art(eg. 1st or 2nd degree BBs  opening their own dojangs-nothing wrong with it if they were planning to progress to a legitimate higher ranks, but some unabashedly self promoted themselves to higher ranks).
This explains some TKD without the complementary /supplementary fighting skills(close range fighting skills, knowledge of pressure points such as the pelvic bone plate) and the poor quality of  so called ITF style practitioners.

The watered down practitioners get their share of criticisms both within the TKD group and outside the TKD group by other martial artists.  WTF stylists mistakenly pigeonhole ITF stylists(usually ITF = non-contact)  as one massive group. It is not. Doing ITF style does not necessarily mean that you are affiliated with ITF. You can be an independent ITF stylist without ANY contact with ITF headquarters.  There are pure traditional ITF-style schools no longer affiliated with ITF and branched out groups of ITF TKD. Within these groups
were formerly ITF members or independent instructors many generations/times removed from the first generation instructor s ITF teachings. Sometimes good, but usually watered down ITF style TKD.

Most often  they are not able to explain why a specific movement is done in a certain way or teach their own/wrong versions of it. eg. I had one BB instructor explain a ki-ma jah seh; horse-riding stance is called so, because it derives ki from the ground; others are not sure why most movements start first with the left; why an elbow strike is cupped by the other hand in some movements is wrongly explained; or what the movement that starts above your head with both your hands drawing a circle and coming down to waist level making a knife-hand strike in the palm of the other hand means-this one found in the early movements of Kwang-Gae pattern; whether the foot or the hand should be out on the same side or the opposite side in executing movements, etc.
by W.Rhee