Do you think now that DDR4 is out there will be a massive price drop on DDR3
Nope, I dont think so. The rate with which people update their desktops is really slow ( playing ds 2 with 8 gb ddr2 right now :D) and if they do its not always 2000 $ i7 systems. The demand for ddr3 will probably still be higher then that for ddr4 in the next few years and then slowly fade away when every new desktop/laptop/tablet/phone/future android butler got ddr4 build in.
No.
DDR3 is still the standard and will be for quite some time. DDR4 doesn't offer enough advantages for it to fully usurp DDR3 at least not for a while anyway. Plus for the consumer X99 is really the only platform that uses it and this will be true for quite some time as even Skylake will have a DDR3 option.