The Canon Cine lenses are not targeted at Rebel owners shooting cute-cat videos to post to YouTube. Or C100 owners. The target audience is professional C300 and C500 users shooting high-end well paid work!
A Canon lens has a different look than a Cooke lens which has a different look than a Zeiss lens. Always use the right tool for the job! So renting not owning expensive Cine Lenses makes sence.
I never talked about taking videos with Rebel Cameras, but don't think who took professional videos with 5D Mark II and 5 III till now was a non professional. House anyone? Iron Man 2 anyone? ;-)
Also consider that there are lot of talented young people and filmakers who aren't that rich, but being rich doesn't mean you make nice movies. Talent does.
What I was saying is that industry thinking the cinema target is only ridiculously rich people, they price everything made for cinema with ridiculously high prices, that's why I was mentioning also the price of stupid bolts and knobs for RED cameras, so it's not about Canon specifically, I could mention lot of different brands that do the same.
Do you think is so expensive to build a stupid metal rail system? What about a stupid follow focus system? Why are rigs so expensive?
I really don't think it's about research, it's just about exploiting the market, I also think that if you know someone with very good optic knowledge you could obtain very high quality lenses for way less than €5000...and I'm talking about completely hand made stuff, considering that with such amout you could easily get an astonishing telescope with fluorite optics.
If you buy a screw, same diameter, same thread, same lenght and material at the hardware store (probably produced in the same factory) you will pay it 198233271239 less than getting it from RED or other cinema brands, so it's not just lenses but everything made for cinema...just my 2 cents.
P.S. The Samyang lenses I previously mentioned are cinema lenses.