Good points, those kicker and alpine subs are rather robust and strong cones and thick rubber surrounds but cost effective because of economies of scale in big batch MFG. . I would't be too worried about that, especially since the drivers are inexpensive. Using it normally would/should result in many years of happy operation, in any orientation. If you have to "upgrade" or swap out the driver in 5 years that's not a totally crazy thing anyways.
"Too much is almost enough. Anything in life worth doing is worth overdoing. Moderation is for cowards."