You are correct about the limitations of upload speeds on EVDO-0. So I see why you made the assumption. But I often get 160kbps upload speeds (and even lower) on my EVDO-A connection at my home, even with upload speeds over 1Mbps. Strange phenomenon. And when it happens, the MAC Index is still low. I've often wondered if it is a specific user hogging all the upload bandwith in my sector, or related to backhaul.
When it comes to more EVDO carriers, that is occurring in some places. However, it is not a uniform deal across the board. Sprint is reserving some PCS space for additional 5x5 LTE carriers (and sometimes 3x3), where there is enough PCS spectrum remaining in a market to do that.
Sprint has prepared a database that shows existing EVDO demand, and projected EVDO demand for the next 4 years at all 38,000 sites. So when Network Vision arrives, they are adding EVDO carriers for existing demand and demand for the next two years, at most sites, so long as they have the spectrum to add the carriers. If it is a capacity constrained market, or if the spectrum is being reserved for LTE additional capacity, then additional EVDO carriers might not be added.
Also, 3.1Mbps is the maximum theoretical speed. The maximum real speed possible on the Sprint network is 2.6Mbps.
Robert