Considering 4K is relatively new to commercial theaters, and far less available in the consumer world, I would say a projector like this could be had for over a decade. It can also do 3D which is almost as new as 4K (in the digital form anyways). You also have to realize that these projectors are highly modular. New boards/processors and other add on features can easily be added on or modded to update it's capabilities. These projectors also accept various lamps to accommodate a change in venue/screen size as well as a whole slew of optional lenses to accommodate a change in venue/screen size.
Considering the cost of these projectors, upgradability should be an included feature. The consumer world doesn't allow this because of smaller profit per sale so they don't usually add an upgrade option because they want you re-buy their product every couple of years.