I'd actually be okay with this if they also stopped using LaserShip. They're part of the reason packages take "significantly longer than the advertised two days" to arrive.
If youre a Prime member and a package misses it's promised delivery date you should contact customer support. SOP is to increase your prime subscription by one month.
Build more warehouses, partner directly with USPS. USPS delivers every day, to almost everyone. Just get your shipments to those sorting centers by 2-4am, and next day delivery for vast swaths of the US becomes easier.