Keep in mind it took (at its peak) nearly 5% of the US federal budget to do it in 9 years.
So doing it on budgets that would be (literally) accounting errors in NASA's Apollo funding is astonishing.
While it's true that a lot of space rated hardware is now available OTS it's coming from traditional Big Aerospace suppliers, at traditional prices. IE "Hooow much for this? WTF? $500 for a bolt?"
What has changed is the very much more detailed knowledge of the conditions along the whole journey and on the Moon itself. Read AC Clarke's "A Fall of Moondust" to realize how much wasn't known at the time.