Every 800+ footer in the state was built when Texas *was* the developing world, like China is today. When these buildings reach the end of their design lives, will their investors see fit to reconstruct them? Now to your question. There are investors who have paid so much for their land (901-999 Louisiana, 3200 Post Oak, and so on) that the only revenue-generating thing it can be used for, besides a parking lot, under current tax codes, is a trophy property. But a trophy property need not be a very tall one. If you build something to command $40 per square foot rents, in fact, it's unlikely you would want to risk building two million square feet of it all at once: you could make a profit on your land purchase with much less construction than that. Will there come a time when enough large tenants want into a submarket for long enough without smaller buildings being built to absorb them (that a supertall makes sense for years to set in motion)? Well, the one time it happened before, it was a bubble. You know what the conditions would have to be for it to happen again. Either a second speculative property bubble, a proud homegrown corporation, a giant relocation, a mixed-use investment with residences on top, HAIF starts a wildly successful lottery ticket pool, or editor repatriates his advertising profits.