Just a bit of history as I understand it ... It's not that Foscam was merged into Amcrest per se.
Amcrest is the company that used to be Foscam USA. They had a falling out with Foscam China for some reason, and decided to start their own brand instead. So, they stopped selling cameras from Foscam, created the Amcrest brand, and switched to selling cameras made by Dahua that have been customized for Amcrest -- and these cameras are far better than the original Foscam cameras.
Foscam-branded cameras that you buy today are from Foscam China, and aren't a whole lot better than they ever have been.