That's what 20 MB blocks require.  That means, you receive the blockchain, that's 84 gigabytes per month.  You send the blockchain to one peer, that's another 84 gigabytes per month.

If you want any redundancy at all, as a true peer-to-peer network should, for whatever reason at all (resiliency, privacy, etc), you need to start adding on redundant pathways, and more data.

All of that has to fit within the data caps imposed by your internet service provider, along with all of your other internet usage -- all of the Youtube videos, other P2P programs, NetFlix, etc, for everyone who uses your connection.  In the US, the vast majority of home internet connections are limited to less than 400 gigabytes per month, most less than 250 gigabytes.

These caps are independent of your connection speed.  They are arbitrarily imposed by internet service providers.  They may grow with technological advancements, or they may not.

Other, developing parts of the world have to deal with other limitations.  Only in a few, highly-developed regions, are home internet connections both high speed and un-capped.

In response to this, there will be some hand-waving arguments involving splitting up blocks into transactions and getting each transaction from a different peer.  And that's great.  That's certainly an improvement over the current network.  But please understand all of the trade-offs involved.  There are trade-offs.