There was this rumor that Polish Governmental Agency for Strategic Reserves panic sold PPE reserves at the start of epidemic, because you cant hand out no bid contracts with full storage! Turned out not to be true https://orka2.sejm.gov.pl/INT9.nsf/klucz/ATTBZ6EY5/%24FILE/i... old PPE from 2006 was expiring in 2020 so was sold in late 2019 (but supposedly still before anyone knew about Covid) when it still had some value. Ironically it was sold for cents on the dollar just to be re-bought later in 2020 at full price or even more.

The article states that the PPE expired. There's also the cost of storage and distribution.

Note that the US NIOSH labs tested out expired N95s and found them to work as well as new ones in terms of filtering capability - the main issue was strap damage.