Can't ethernet do 500m? I think it's specced for much less but I imagine you'd still get half decent speeds. I don't see how this is revolutionary. Actually doing a bit of reading it seems some earlier forms of ethernet over coax could do 2500m! Revolutionary would be if it could do 10km+ so it could actually serve more than customers a block away from the CO. Seems ADSL2 is still the winner for copper broadband. Or cable I guess.
No, it's not. ADSL2 is only good for up to around 24mbps. It has advantages over VDSL2 (better rates/performance on *longer* loops), but otherwise for copper speeds over 24mbps those are only done via VDSL2 or VDSL2 + loop bonding. In Canada, 100mbps is already being provided via loop bonded VDSL2. Obviously that doesn't apply to long loops though. Personally, I prefer cable, it's what I have at home. But from a technology / work perspective, I find DSL fun and interesting.
G.fast isn't something that will turn the industry upside down overnight, or at all. But considering the existing infrastructure for VDSL2 (which are mostly of the "fibre to the node" variety), it makes sense to push the footprint and available speeds for eligible customers using G.fast. Why not?
It's something that will give some people more/better options. Obviously if your inside wiring sucks, that will still hold you back, G.fast isn't going to change that.