Yes they didn't last because the criminal phones didn't have the resources to run a secure phone. Cape looks like it does or will, it is funded heavily by VC and has a media buzz about it and is pumped everywhere at the moment. Everything has the possibility for a backdoor, if Cape are getting this much press and funding they most likely have in built protections and surveillance against the phones becoming used for crime related activities, I haven't checked though.They will succeed for how long is the question…
Previous projects didn’t last.
Also with these big name investors there is a big possibility for backdoors.

