Williams 'defense'
It has to be kept in mind that our major sources here are highly biased. Gygax of course has no love for those who replaced him, and from the view of WOTC, the worse they make TSR look, the better their own efforts seem.
We can note here GG's claim he had to change the name of his movie effort because of TSR's bad reputation. But a petty $10 mil business having a reputation in the $bill of Hollywood? Doesn't seem likely. A much more reasonable explanation is that Hollywood was completely unaware, and uninterested, of TSR, while the name Dungeons & Dragons at least got him in the door.
The picture of Williams taking over a secure business and running it into the ground also needs modification to be believed. We are told the business was about to be shut down by the bank not long before. GG would like for us to believe that he had somehow gotten it on a solid basis during a brief period he was in charge, but this seems most suspicious. He has not shown any great executive talent since then.
Far more reasonable is how many of us recall those 1st Williams years, as a period of great success for D&D and TSR. This is what put the business in good position, and unfortunately why it ended up even deeper in debt. The bank, seeing it do well, was willing to extend additional credit when the decisions started to go bad. [An unfortunate problem with executives is that they stay in power too long. One rule of management for the board of directors is that the CEO should retire in 5 years, or be fired in 6.]
And the story is told that much of TSR's trouble was tactical. Somebody got uppity with a major bookstore chain, which not only stopped selling TSR, but demanded cash for returned merchandise, lots of it. That sort of thing can put a solid business on the ropes.