My opinion on this sort of thing, for what it's worth, is that...

My opinion on this sort of thing, for what it's worth, is that it is very hard to put a price on durability.

It's kind of mathematical. If you look at the present value of future cashflows, especially ones those that can be expected to be growing (even if only moderately), the increase in value one gains is staggering. For instance, you can have a business that looks very profitable today and that has a high growth rate, but if the business were to die 20 years from now, the actual value of the business for someone buying today, would be far, far lower than a simple projection of current earnings and growth rates would imply.

In short, the effective growth rate that a death after 2 decades would correspond to, from a valuation perspective (for someone buying today) would be far, far lower than actual current rates.

This is to say that a lower growth rate today, that has a higher certainty of persisting for a lot longer, can be expected to be worth far more than a higher growth rate with less certainty of durability.

That is probably a very convoluted way of saying that maximising the safety, strength and thus durability of a business, is very hard to put a price on, especially when (well, actually, only if) the business has an ability to reinvest its earnings at attractive rates of return. That, in my mind, is the value of the property portfolio (as @travelightor is probably suggesting, in a less tedious fashion). I'm even happy to forgo franking credits for the benefit.