This IS the "best" glass. It's just not the most expensive glass. The whole f/4 set is pro stuff with the usual gold rings. Check the reviews by reputable reviewers. In 70-200 the f/2.8 edges out the f/4 in sharpness by a hair so small you'll never see the difference in any picture printed, projected, or displayed on an LCD monitor. The 16-35 actually is sharper than the 14-24 but has more (correctable) distortion at the short end. I've loved my 24-70 for years but I have to admit there's not much to choose between it and the new 24-120 f/4, and the 24-120 has VR. If you check you'll find Nasim Mansurov agrees with that assessment.
The real question is whether or not you MUST have f/2.8 for very narrow DOF. If you must, you'll pay more of course, but you'll also wear yourself down if you try to carry it around. Nowadays, considering the ISO performance of current cameras, f/2.8 essentially is studio glass unless you're Joe McNally going out with trucks full of lights, gear, and assistants.
If you want to brag about how much money you've got in lenses, go f/2.8. If you just want trustworthy gear and really fine photographs, don't be fooled by price differences; go f/4.
Oh, and I had to come back, Roger, and point out that your lenses haven't gone up in "value." They've gone up in funny-money, dollar-denominated price. You have to take inflation into account.