Altium is just like any other PCB design software, new chips and...

Altium is just like any other PCB design software, new chips and components are catered for by simply creating the schematic symbol and the PCB footprint symbol in the software. Altium can either do this (they have a component creation team responsible for new parts), or the PCB designer can do it themselves. It's anywhere from a few minutes work to 10's of minutes depending upon the complexity of the device. Maybe a few hours for a huge processor chip with a 1000 pins.
This is daily bread and butter stuff and really has nothing do with Altium itself, no PCB designer will care if Altium doesn't have support for some obscure new chip, they can just create the part themselves (and usually do).