A small reality check here. I hesitate to do this prior to tomorrow's FOX interview, but:
Try to remember, next Presidential is unique in many ways. First time since 1952 we have had a Presidential without an incumbent Pres or VP on the ballot, and that if one does not count Truman's brief flirtation with a second term. Incumbents of course, do not always win (Ford, Carter, Bush the First) but they severely limit fundraising by prospective candidates.
We already have twenty years of a two family dynastic hold on the Presidency, Hillary's prospect of making that 28 years only adds to her "hard negatives" which run between 35-38%. In polling, a hard negative is an "I will never vote for X" response. One third of likely voters is a heck of a speed bump for anyone running for any office.
Forget Gore, who by the way, is the Senator Thompson replaced, and who could not carry his own state in his Presidential bid. Gore can split the early money, may be holding out to jump in after Hillarious and Osama Bin Barack cut each other up, but he is IMHO, unelectable.
The other unique feature of this election is the early start. Bush still has 21 months+, even with the compacted early primaries, there is plenty of time for jokers to jump out of the deck. Thompson has plenty of time to play it close to the vest and stay with his unusually high name recognition career in TV and radio. As the early sprinters collapse, that name recognition becomes a $100 million jump start should he "change his mind".
Could be wrong, but I look to Sunday's interview to be a presentation of his credentials accompanied by some lively tap-dancing denial of his intent to run, AT THIS TIME.
Your summary nails it on the head. Fred is biding his time. He knows, McCain knows, his staff knows, hell everybody knows that his campaign is already tanking.