After a few months in microstock, I have some little sales in different agencies. More or less, I agree with the "earning ratings" on the right: SS is my best earner, I have some sales at FT, DP, P5, 123, BS, CS .....
Envato is in the middle tier: I have not a single sale (with 198 images there now), not even I see a single view for my images. Well, I found an image with a single view in July, but as far as I searched, that's the ony one.
Maybe I made something wrong? I can find my images in PD by keywords, so I assume buyers can find them too, but no news about a little sale or some views. Strange.

The rating for Evanto is for the combination of their sites, not just PD.

I have a small number of images on GraphicRiver, with the vast majority of my work on PhotoDune.  Envato's sites bring in regular sales for me.  They run #4 behind Shutterstock, 123RF and iStock at just under 7% of my total for the past year.

It may be necessary to have a large portfolio to get noticed at Envato, but mine gets regular attention and regular sales.  Given the minimal effort to submit, I'd suggest not giving up so quickly.

I have a small portfolio of 250 images. I had 3 sales in my first month there. And with that I am listed at no. 12 under "top new authors" 

Well, I have regular payout every month. For me PD is doing better ($$$) than Fotolia, DepositPhotos, Pond, Canstock, Veer .........
Port size (6300) is more less the same on all sites and I'm satisfied with them so far.

Half my portfolio about 400 images

September 2012   3 Sales   $2.31
October 2012   15 Sales   $6.93
November 2012   6 Sales   $4.95
December 2012   4 Sales   $4.29
January 2013   10 Sales   $8.91
February 2013   9 Sales   $7.92
March 2013   6 Sales   $4.95
April 2013   13 Sales   $10.56
May 2013   13 Sales   $11.55
June 2013   9 Sales   $7.59
July 2013   7 Sales   $4.29
August 2013   2 Sales   $0.99

OK, then it is possible to have some sales there.
And "upload and forget" is a good tactic, as PD (via FTP) is easy.
But zero sales zero views are a bit bad for an agency in middle tier. Yes, Envato overall is in middle tier, not PD, but it seems to me unfair to consider many agencies as a single entity when, from the contributor's point of view, they are different sites to which upload different media.

The only way I know for seeing the views is a pain:

you must enter Author dashboard, then find the voice "Analytics" in the "author resources" box. You are asked to enter your username and an API key (you have to obtain an API key previusly in "Settings/API keys".
After that, you can see statistics for your images, but AFAIK, only one image at a time.
It's a long job, so I searched statistics only for a few images, those who had sales on other sites, and was able to see a single view.