Citation please. Are you really sure this applies to modern front-end web app with reasonable complexity?
Of course if your web app relies on all kinds of sexy stuff then you're going to have to convince yourself that those people don't matter.
Your original statement was broad and general, not qualified. Your anecdotal evidence is not sufficient to support this claim.
In the context of the discussion about supporting IE 8,9 and 10 and using your terminology flexbox (which IE 8-10 doesn't support) seems to be "all kinds of sexy stuff" and "not keeping things simple". Right, got it.
You could be a liar, idiot, troll, or just really love IE. Why would anyone take your word for it.
You omitted the possibility that I might be right, am not an idiot, am not prone to either lying or trolling and absolutely detest IE (and have not used windows for a really very long time).
> Why would anyone take your word for it.
Please don't. Ignore me and whatever I write here on the off chance that there is a grain of truth in it and that it will make you money.
Forgive me if I did not anticipate the Spanish inquisition demanding proof for something that to me simply makes good sense. Feel free to offend your users, to limit your products to function only with the latest browsers and to spend your marketing money to attract people that can then not use your product.