Feel free to find things that say the opposite, i've never seen a study that says "users will choose the slower service, if it's 'better', they just don't give a crap".
And sure there is a diminishing return, but if your latency times are 1s or greater for a web based service, you are almost 100% guaranteed to be losing users/conversions/etc.
Actually, performance is quite important for scalability. A lot of sites written in Ruby / PHP have big scalability pains if they get popular. Twitter had to be re-written from Ruby to Java. Facebook had to completely rewrite PHP's compiler to make it close to a compiled / statically typed language.
Joel Spolsky mentioned how StackOverflow only needed 3 servers to run it for a really long time, because it was coded in a compiled language. [1]
It's nice to see how fast Go is already. It'll probably be a couple years ago, but it should improve once they start working on the optimizing compiler.
No, it doesn't imply anything at all about whether speed is a big deal or not.
At best one can conclude that concerns about performance aren't as important as other considerations which make Rails/Django more attractive. My opinion is that these other considerations are more along the lines of cost of labor and ease of learning than anything else.
