You’re talking about a lot of surfaces, and cleaning crews can’t come through all the time and clean every few minutes or so. You just need to give some bacteria a foothold in one spot for long enough for someone else to touch it and move it along. I’ve read reports that say that doctors’ ties and white coats can be pretty damned germy since they don’t get laundered that often. (Looking at my own white coat hanging on the back of my door, I can attest to that.)
The cleanser may not be in place for long enough to work before being wiped away, or might not get into the cracks and crevices harboring bacteria. People might misunderstand the effectiveness of a hand-cleansing product - that alcohol-based hand sanitizer is great, but not 100% effective - or not wash long enough to scrub away all the bacteria, or might scrub long and hard but some bacteria stayed under their nails and later works its way out when they’re ungloved.
Plus there are places that germs land on which people don’t really think about, and which can’t be cleaned in that fashion, like patient charts. I’m very certain that when I worked in pediatrics, I would catch the kids’ colds - without ever seeing 99% percent of the kids - by handling the charts after they came back from the clinic. Kid coughs/sneezes in exam room near chart, or hugs nurse/holds nurse’s hand/shakes doctor’s hand, or the doctor or nurse picks up the viruses by just examining the kid, then touches the chart. Unthinking me would pick up the chart to deal with it as needed, and later touch my eye/lips, and presto, cold transmission. Get enough of those surfaces and enough unthinking people who move germs from there to elsewhere, and you have a great vector for disease.
As previous posters stated, most “superbugs” flourish only when you’re dealing with an immune-compromised or otherwise very ill person. The sheer amount of other competing “bugs” that are out there will crowd it out, and your immune system will keep it suppressed too - it might not feel like it at times, but you don’t catch every cold, etc., that you’re exposed to. Most health care workers’ families are more or less healthy like the average person, and so unless they’re very unlucky or unwell, they’re not very likely to catch it either.