But there are serious known bugs in IE10 and IE11 flexbox implementations. They will never be fixed, so when IE11 market share drops below 5% I will use flexbox

But there are serious known bugs in IE10 and IE11 flexbox implementations. They will never be fixed, so when IE11 market share drops below 5% I will use flexbox. We're talking about perhaps in the year 2020. HTML/CSS is still not suited for app development and due to browser inconsistencies that will remain true for decades to come, perhaps forever. Apps in browsers is doable, but a more cumbersome than one might think.