I close sites all the time when they fail to work quickly. I have aborted orders on sites midway through when the interaction became sluggish enough that I wasn't confident in the value of the product anymore.
This statement reminds me of those Gordon Ramsay shows where a restaurant owner says "the customers like my food!" when it's obviously subpar. The fact is that the customers that didn't like the food politely go away and don't come back.
Your other points get more directly at framework performance versus other performance concerns. I have fewer opinions about those.