Etherium hashrate. Build your miner or buy from Genesis Mining?

First some details about mining Ethereum and then arguments.

Bitcoin mining sha256 is a gpu/cpu oriented mining. That's why it was possible to integrate more cpu/gpu in one chip and make an ASIC, smaller, faster then graphic cards.
Ethereum mining, dagger-hashimoto algorithm, it is ASIC resistant. How? Well, by using graphic memory, and a lot of it. Mining happens on a DAG file, every miner has to work on that file that changes with every operation. And it requests data from all over the file. So for every simultaneous hash operation you have to have the dag file in memory. That is why to create an ETH/ETC asic for every tiny miny miner in that ASIC chip you need 2-3 GB of video ram.

Difficulty does not affect the hashrate, an example is etc and eth. It affects only the reward. Eth has 10x difficulty of ETC, same miners, same algorithm, even same coin (hard forked). Yet you mine ETC and ETH with the same hashrate. Even the income in $ is the same. In conclusion the rise and fall of the coin price will affect the difficulty as more miners come and go driven by profit, but it will not affect the income in $$. You will get less expensive coin or more cheaper coin. (search google "etc difficulty chart" and "eth difficulty chart")

What will affect your income in time, and the hashrate is the increase of the DAG file in time.THIS WILL drop the hashrate in time. SAPPHIRE R9 280x (22 Mh/s for Ethash)......that was in april /may 2016. Now barely 12-15 Mh.( Again, search google. You don' have to take my word for it.)

Dag file increase is approximated to be :
The 2GB limit will be hit around mid-December 2016
The 3GB limit will be hit around mid-April 2018
The 4GB limit will be hit around mid-September 2019

This WILL have a direct impact over your income if you build your own miner, opposite to buying hashpower and not have to pay for electricity or hardware.

Again... think this is worth it only because dagger-hashimoto is ASIC resistant. Integrated chips have a fast evolution, I do not think that sha256 bitcoin hashrate is worth buying, as it will be dwarfed by new chips and ASICs.

EDITED to answer @[-]kyle.anderson in the replyes:
Edited because I don't think I can post pictures in the reply.
This link:
https://www.cryptocompare.com/mining/guides/how-to-mine-ethereum-the-easy-way-an-ethereum-mining-contract/
And this guy being wright at the time in the reply (on the article from the link):

The eth hashrate is even cheaper now , 4,900.00 USD 175 MH/s, that's 28$/Mh, 27 using a promo code, not 44 like then, and it is for 2 years not 1. it's on sale.
His 4x 7990 bought a year ago, yes 200Mh then, now less than 100 Mh. And 7990 price a year ago........just search....and now they are garbage.
So I think he would have been in more profit with a mining contract. Imagine how much the hashrate will go down in 2 years, because etc is not going POS and you can also mine etc with it.

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