Of course there are exceptions where biking won't work, but the US is enormous. There are plenty of places where the weather is much more forgiving than almost any part of Europe. The US is not some "exceptional" geography. Delivery bikes are spreading in boiling hot Spain and freezing cold Finland. These excuses are mindboggling.

its better for a shipping company to run a van that does efficient same day deliveries than fragmenting shipping using utility vehicles that wouldnt handle shipping surges in certain periods, which also not sustainable from a business stand-point, and probably adds more to emissions.

Add more emissions? More bike emissions? Even in Europe, it was financially better for delivery companies to use vans until they changed the policies and incentives. I have no idea why people like you are against this. Yes, this won't work in some places, but there are many places where it will work. We just need to demand better laws and incentives.