Do most knowledge workers actually put in exactly 8 full hours a day on work tasks working from home? Probably not.
But as a professional software developer since the 1990s the same was true for myself and virtually everyone I know when I worked in an office.
The way I 'waste' time is different now, but arguably a lot better (eg. me taking a nap just before or just after lunch improves my productivity in the afternoon a lot more than me fucking off on slashdot for extended periods of time in the office did back in the day.)
(And whether or not this not-directly-related-to-work downtime is really a time waste is extremely debatable, as switching thorny problems into the subconscious realm often turns out to be one of the best ways to actually power through them in my experience).