Part of it was that users were terrible at updating browsers. You needed to support Internet Explorer 6, or cut off a third of your customers. It sucked. Now e

Part of it was that users were terrible at updating browsers. You needed to support Internet Explorer 6, or cut off a third of your customers. It sucked. Now every browser gets updates, automatically and aggressively. The only real outlier is Safari, but even that updates way quicker than older browsers used to. As a result, who needs backward compatibility?