short range cargo bikes for non-windy city use (good pavement) see this thread: 
https://electricbikereview.com/foru...ce-your-ideal-set-up-or-your-wish-list.25696/
You can get an unpowered cargo bike for <$2000 US.  Powered?  The yubabikes.com entry is about $2300.
Other US stretch tail cargo bikes are xtracycle.com edgerunner bosch electric and radwagon from radpowerbikes.com  I don't know if radwagon is mid drive.  check their websites.
The only mid-drive that can be ridden without power without a huge drag is the yamaha.  And I don't know of bikes that have that.  I use electricity on my cargo bike to maintain usual speed into a >9 mph headwind, or stretch my range from 30 pedaling to 60-80 with assist.  No wind, normal 30 mile day, I pedal, it is good for my heart & lungs. So I use hub drives, geared if I can get it because geared hub doesn't drag at all unpowered.
If you live in a location with no wind, there is a category with a bin in front of the rider and the front wheel driven by a chain from handlebars.  These are pretty expensive.  They are hot in Amsterdam, which I assume is not very windy.
I find 26" wheels minimum necessary to cope with the pavement in my area.  A front and rear suspension could cope with that but because of variable weight I don't think cargo bikes have them.