There's also the 'minor' little detail about Lance being given less than a 40% chance to live when he received his diagnosis. His former team Cofidis assured him that they were 100% supportive of him, then dumped him, so he not only had to fight to live but to get back into world class racing shape to earn his way back to a sponsored team again too.
I've heard that he is fiercely loyal to each sponsor who actually did stick with him and that even though the USPS team may have other product sponsors, there are a few where Lance differs as he's committed to them for good now. I think that Nike even put him on as their employee so he'd have health insurance benefits.