I can see that mounting film when the cost of development is 2 Euros would not be profitable. On the other hand, thedarkroom.com charges $14/roll plus shipping. With the current changes, I have seen nothing to suggest that the price will be lowered, and have every reason to believe that when mounting is re-available it will be at an additional charge.
I know that I can mount the images myself. In fact, receiving unmounted film will allow me to scan the complete image before mounting. On the other hand, if I am having to do all that work myself, I might as well develop my own E-6. I could probably modify my workflow so that I could mount images as I scan them - that way I can be 100% analog and hybrid at the same time.
I will likely still use thedarkroom's services from time-to-time as it is convenient to have pre-paid mailers (no trip to the post office) and scans emailed on development (if the slides are lost, at least there is some low-res preservation of the images). I guess what bothers me the most is that this announcement comes out right as Ektachrome is released.