Point taken, what you say is perfectly reasonable.
But I happen to think you could have allowed me a little poetic licence. Just getting arms and legs to me is not much different to not getting anyone all... but I accept all you say. Perhaps you would have prefered a more accurate, needed a defense and got players that were nominally called defenders but in fact turned out to be nowhere near good enough. And for that I hold TK and the whole senior management of the club totally responsible because that is what I beliebve to be the case.
In the end, we shall have to see whether lessons have been learned, I suspect not but hope springs eternal.
I didn't mean to be derive you of any poetic license, it was just in my opinion an important difference. I fully understand and respect that it may very well be no need to take what you write so literal however, and appreciate your explanation above. I still don't agree on your conclusion that the defenders brought in were so bad that they could never be good enough, but am happy to concede that this is very much an area where opinions can differ a lot.
So, we may disagree on whether the plan was good or whether recruitment was reasonable or unreasonable. We may also disagree to various degrees on how good, bad or indifferent the intentions of the upper management were, or whether or not they are completely incompetent. I believe however that we can agree that at the end of the day they failed with their objective (since I believe it is fair to assume that they at the very least aimed for survival). For that I also agree that they have to take responsibility. If that is by stepping down, or improving doesn't matter much to me, as long as we are not stuck in a downwards spiral.
I join you therefore in hoping that lessons have been learned, albeit I am probably a tad more optimistic about the possibilities of than you are.
Cheers to a good summer 
I agree the clubs objective from 2016/17 to 2022/23 is “survival in the premier league
payment system long-term” (ie FFC recieving premier league tv money including parcachate payments for 20 years +), which means never having a squad that can get relegated and not bounce straight back up with automatic promotion. Tony Khan can fully redeem himself if he can give FFC a squad 19/20 better than Newcastle 16/17, Wolves 17/18 or Fulham 2nd half of 17/18. A good DoF avoids relegation, but a great DoF has prepared for a comeback in advance.
FFC and TK haven’t failed long-term yet, we went close in 17/18 to failure, but now we have the money to get back to EPL. What Fulham needs to avoid is the blame game for the relegation, we need to focus on being better than 17/18.
Being better than 17/18 needs to start with step 1 - ensure Mitro, Anguiisa, Bryan and current 17/18 squad members are at FFC all next season, step 2 - buy Kalas/Piazon to add depth immediately, step 3 - replacing Sessegnon with a premier league winger immediately, step 4- get a top championship right winger and backup striker, step 5 - have a good pre-season and step 6 - buy players to fill any other gaps that appear around deadline day or earlier.