There is basically no market for this. The set of humans who want a turnkey DD-WRT-type solution is functionally nonexistent. The target audience for this is people who won’t actually tinker with it but want to imagine they would. Anyone who would actually tinker with it doesn’t need it preinstalled.
Dropbox is an odd comparison because it’s not the hacker solution at all. The market for Dropbox is indeed normal folks who do not want to tinker. They want it to just work. (I buy Ubiquiti because I want it to just work.)
I assure you, this market exists. I own a RaspberryPi and have never once used it. In fact, I know several people who own several RaspberryPis and don't use them!