Let's assume each user does at least 1 transaction per day. There are 144 blocks per day.
A million users * let's say 100 bytes per transaction / 144 = almost 1 MB per each block = 6 Mb / hour constant incoming traffic to every client.
So you think 6 megabyte (BTW, Mb would be megabit) per hour is too much? I mean, a single SD card in my smartphone could store the total *raw* traffic for more than a year. But as was already pointed out, there is no need to store the complete raw data on a smartphone client.
And on a full node? Well, we are not living a decade ago, we now have terabytes for a two figure price, and believe it or not, we will have petabytes as cheap in the future.
So those while those number may look huge for the uninformed, those are actually tiny. At the moment the bittorrent network alone produces a network traffic of around 10 petabytes per hour, some 7 orders of magnitude above the your imaginary bitcoin network, and probably 10 orders of magnitude above the current bitcoin network.
But seeing that you are trying to spread FUD in some other thread, well, maybe you are just trying to to that here too