I think it depends on the materials of the o-ring. For most modern housings that use silicone or fluorosilicone o-rings regular lubrication will keep them soft and "stretchy" and they should have very little compression set. For some of the older housings that use nitrile for main o-rings, even regular lubrication will not prevent a bit of hardening from ozone and sunlight so those I would replace yearly (if you dive a lot).
According to the financial press, their camera division has not made a profit in 3 years, camera sales are projected to fall by half, and market share is headed for the low single digits. Even if the OM-D and PEN lines seem successful to enthusiasts, a well run global company is unlikely to keep that kind of performance on life support for long. On the bright side, maybe we'll see some closeout deals on EM-1 bodies and m4/3 lenses!
Then again, I don't think Olympus is terribly well run, but that is a different problem. Cameras are less than 15% of their total business but the EM-5 was specifically called out in the annual report as being important.