What Has Happened to Mail Delivery Drivers?

We have had a lot of delivery delays in our location because of the ice on our street.

This is not because of shipping issues, supply issues, or even shortage of actual delivery staff in our area. Instead, according to the senior (older, 40+ years old) delivery drivers at USPS, UPS, Fedex, and others, all/most of the drivers under 40 years old won't deliver if the roads are too snowy or icy.

I don't know if this is backed by their unions, but that is the only way I can think of that they are getting away with refusing.

So even when something arrives in our area at the distribution center on time, ever since winter weather resumed for the winter, we are repeatedly not get deliveries for up to a week until, generally one of the senior (older) drivers is on shift for our zone. 😞 

This has been particular frustrating because we were trying out many (5 so far) of the healthy prepacked food delivery services, but the food has been ruined every time, by the time it arrives (we get our money back from the food companies fortunately, but I feel bad for those companies).

Whatever happened to "through rain, wind, sleet or snow, the mail has to go"?