You never can tell what's in McClay's mind, but if he wants to captain his own ship, none of those things matter. Most fans are looking at this from a fan's perspective, rather than that of a high achiever's. A cushy job in a corner office and a fat paycheck aren't what motivates them. Same reason some executives in other industries walk away from comfortable jobs to start their own companies.
If McClay is who I think he is, he'll either take this job, or he'll turn it down for reasons different than fans above think. He'll turn it down because he doesn't believe the Washington organization is right for him, not out of loyalty or comfort in Dallas. I can't imagine a guy like him with options would go to Charlotte, they're a trainwreck. A guy who's been busting his tail in pro football for over 30 years wants to continue to ascend, and the top of the profession is to be a GM, not a fake one sitting under Jerry's nose. Whether it's now with Washington or somewhere else in the next few years, McClay's relationship with the Jones family will come to a head and they'll have to acquiesce, or he'll be gone (provided he continues to be successful in the meantime).