NO HUMAN can always know what friction will be available all the time... like night, like spilled antifreeze, like fog, like panic caused by critters or humans. We know most of the time..... BUT NEVER ( never ever, never ever, never ever) ALL OF THE TIME!
That is what ABS is for. Adds another layer of protection. This does not mean one no longer has to practice the fastest, safest best braking possible. This does not mean one can ride with complete abandon, totally care free and take unusual chances etc. BTW... ABS does not work to good when you are cranked way over. ASK ME HOW I KNOW.

OTOH... if one always rode the same roads only in daylight and stayed away from people and critters then the ODDS ARE ABS is not going to be needed .... probably. It reminds me of a airliner pilot joke. The Captain gets on the PA and announces we will probably be making a safe landing in about an hour. SAY WHAT? PROBABLY .... hey sucka... aint no probably..... make the damn safe landing!

What fun is there in riding the same road every day? The same road that you are perfect on the brakes. The same road where no unforeseen out side forces can ruin your day...

I ride to enjoy as much as I can inhale and process. This means traversing unknown bitumen, asphalt, concrete, and every thing in between. All it takes is preventing one spill, and the cost of ABS is paid for 10 fold or more.