I understand what the OP is trying to argue. In the past accruing 300k RDMs for about $4k was easy. Today to get 300k RDMs would cost $27,200. So while before you could literally spend airline miles like funny money (and many, many people did), it would make sense to evaluate does it make sense at that XYZ redemption to use miles, or to pay cash. Before, outside of very minor instances it was almost always better to use miles (cash is king). How many of us were flying to Asia for $500 and then getting 35k RDMs for it? So spending 25k miles on a $300 ticket wasn't absurd.
Today, unless you MS the vast majority on here will earn fewer RDMs, which in a sense make the miles accrued "more valuable", since the ability to replenish our supply of them went up in price. So while "hoarding" makes no sense, the ability to easily earn 400k RDMs a year is gone for many of us, and so the willingness and ability to spend in large amounts diminishes.
In theory over the long haul, this should help increase the availability of awards as people earn fewer miles and ultimately use more than they are earning each year.