Some features, like SPDY, can be implemented even though not all the browsers support it -- which means that those that don't will find that their users think their browser is slow.
Some features can be emulated with things like long-polling.
And some (WebGL) can't.
I doubt you will be right about those features that can be replaced or emulated but you are properly right about those that can't.
Then again every day we choose to exclude some customers (you only speak Japanese? Well sorry then).
Some features, like SPDY, can be implemented even though not all the browsers support it -- which means that those that don't will find that their users think their browser is slow.
Some features can be emulated with things like long-polling.
And some (WebGL) can't.
I doubt you will be right about those features that can be replaced or emulated but you are properly right about those that can't.
Then again every day we choose to exclude some customers (you only speak Japanese? Well sorry then).