Why should prices come down (in theory) in an educated society with a well-run government? In Chapter 1 of Robert Kiyosaki's &quot;Rich Dad, Poor Dad&quot;, the rich dad says: &quot;In an educated society with a well-run government, prices should actually come down&quot;.
Is there any economic theory that would support that claim?
Would that require a government/society of a particular ideology?
Sorry for the lack of research, but I was never big on studying economics. I'm mostly a software guy and an insect geek. I'm mostly looking for pointers - e.g. which economist I should read in order to understand where that quote is coming from.
Is there any economic theory that would support that claim?

As far as I'm aware - no.
In science of economics it's considered that predictable mild inflation is better than deflation (i.e. prices going down), as deflation causes higher unemployment and risks to spiral into self-systaining cycle which can be problematic to break. Also, inflation allows employers to decrease real wages of workers over years by just not raising wages (or raising not high enough). And unlike deflation, inflation stimulates people to invest money, rather than sit on them doing nothing, knowing that they will be able to buy more with them if they will just wait.
There is possibility that the rich dad supported the gold standard, for which it's indeed normal to experience deflation when economy grows (so well-run government would really just mean one that supports gold standard). But gold standard opens its own can of worms and very controversial choice at the best. For an example, there was established link between countries recovering from the Great Depression and their abandonment of gold standards, earlier abandonment of gold standard led to faster recovery