They may very well be, but with Verizon pushing to VoiceOverLTE (VoLTE), the need to have a EVDO/HSPA Network, and an LTE Network is very minimal.
Obviously to support legacy devices, you will need to maintain the other network, but Verizon has already said their LTE Network will be larger than their EVDO Network by the end of this year. It may be a 5-10 year time frame until EVDO/HSPA is phased out entirely, but I wouldn't expect them to dump much more money into HSPA/HSPA+/HSDPA. Pretty much if you have it, you have it. If you don't, don't expect it, and wait until LTE comes your way.