To play devil's advocate...
You could also argue that it's a lot of money to pay for a keeper who only has a year's experience, in a poor side, was relegated and looks far from the finished article.
You could also argue that whoever replaces Henderson has big shoes to fill. As we enter our second season and hope to consolidate and push on, many might want someone more proven. Yes, Henderson wasn't proven, but he's the best of his generation, so it's less of gamble. My feeling is that the keeper has to be solid and dependable, as we look to build. We haven't really got the time and space to nurture a youngster, who may or may not come good.
Then you factor into the equation that we reportedly have very little to spend, none of us know how much, but for a club with a smaller budget as ours, £18.5m feels a lot for someone so unproven. If it doesn't work out, we have a big problem and a presumably sizeable chunk of the budget gone. Especially when you factor in that we need a CB, RWB, RCM, striker or two and are looking at a LWB.
I think the point that
Kanye makes is that whilst, yes, it's partly circumstances (you can only do what you can, with the squad you're on loan to), it's a very different trajectory to someone like Henderson who has stepped up a division each season, proven themselves at that level and been successful/comfortable at that level.