The Mariners may have a few holes, but if you'll look closely and count on your fingers and toes, you might have noticed that they are winning more games than they lose right now. That makes them a "winning" franchise. And one not too danged far from making a move up the AL West ladder I might add, especially if they can build around King Felix in their starting rotation.
They haven't spent their money wisely in recent years but you can't pretend they don't have it to spend. The Mariners are a team with above average fiscal strength right now that's willing to spend what it takes to keep key players happy (see Ichiro) What on God's green earth makes you think that Felix wouldn't be one of the players they'd most want to keep happy?
they were polite enough not to hang up on Theo Epstein instantly. That's not the same as listening and you know it. Trading a player like Felix for less than a perfect return will doom that franchise. They're better off paying the money to keep Felix and then going to the free agent market looking for high-OBP, high SLG types to flesh out the middle of their lineup and finding a #2 starter.
Whatever fans said this are nearsighted. For one thing, the kid's in his mid 20's and still getting better, for another, this is a team that just spent $20M for Ichiro Suzuki, who certainly won't get any better and doing to be in major decline before the end of that deal.
The things holding this franchise back are a combination of the aftermath of the Bedard deal, and the Silva and Washburn contracts. If they could resolve these issues they'd be able to build around Felix and get into contention pretty quickly.