I kind of doubt Apple can launch iPhone5 in June, especially if they want to equip it with LTE radio. They will probably launch it in early Fall like iPhone4S did last year.
According to industry news, Qualcomm is having trouble with production of S4 processor, new LTE radio chips on 28nm process of TSMC. They have hard time meeting demands for S4 chip as most phone makers are jumping on it. So their new 28nm LTE radio compatible with non-snapdragon AP will be somewhat delayed until Fall. I think this is the same issue that delayed Exynos/LTE combo as well as LTE iPhone5. So I guess Samsung will go all out with Exynos/LTE from Q4 or Winter. That's good timing for next Nexus.