Research, development... production costs of making what will no doubt be a limited run of essentially bespoke devices (even if they are built using "open" hardware).
There is always a fairly significant amount of time, effort and money spent on bringing a product to market... My guess is that they're just trying to recover these costs. Sadly, in a market that has two well established leaders which are already at significantly lower price points, it is going to be difficult for them to sell many units.
Imagine if Apple/Samsung were selling $500 flagship smartphones... and Google/OnePlus showed up with a $1000 smartphone... because that's pretty much what the Passport folks are attempting to do here

Making it worse is that most of the OS is coming from ColdCard and so is a large amount of the hardware design. Yes, they still have to do a lot of work / tweaks but they already know what and how things work, they just have to tweak it to what they want.
Hoping the price drops before release.
-Dave