I probably used to spend on average about 1 1/2 hours/day with my 2 girls: maybe 30 minutes in total for feeding, changing the water, scooping the litterboxes, some time for playing, and the rest of it giving scratches, rubs, brushings, and generally having face time with them. When I was busy, they might have only gotten 15 mins or so with me.
Now that they're older and have medical conditions (both have high blood pressure, one is blind and in CRF, the other suffers from very frequent constipation), I spend easily 5-6 hours/day, 3.5 on preparing food (they only lick wet food so it's a whole process to get it smushy enough for them), 20-30 mins. getting meds ready, 30 mins. cleaning up after whoever's vomited or pooped out of her litterbox, about 45 mins. of quality time. I routinely work 8-11 hours/day, every day, including weekends, while school is in session, so playing tends to fall by the wayside. That's why it's good to have at least two kitties - they bother each other when they're bored.
However, I think my situation is fairly exceptional. Most kitties wouldn't take nearly that much time.