the idea of "wait until that actually happens" its a bit worrying and dangerous. what should be considered the simplicity in scaling well and not necessarily installing powerful and expensive servers right away. In some view I agree that he should wait until the system reaches that number of users, but he should be able to estimate that sooner than later and design the system and choose technologies  that are able to scale to higher number of servers easily

you're also listing technologies and IDEs to use without knowing much about characteristics of this system. one can end up with some of the items in this list, but this is too fast jumping into conclusing.