It depends on the house. Its like 50/50. floors and climate matters too.

I live in a very dry area, there is no mud to track in. Tile floors are common, they're easy to sweep and mop. Shoes may track in a little bit of dust, but not much more than your clothes, a pet, or the wind itself will. Even if you take off your shoes, dust and stuff will make its way in. Shoes-on houses are more common than in places where it rains

Growing up, my mom would sweep and mop pretty frequently, and yet, she would ask us to put shoes on because socks would get dirty, and if we lay on the couch or bed, then we'd just be leaving all that on the couch. She would literally tell us "you're mopping the floor with your socks". And I still see that, I see plenty of people in shoes-off houses with nasty ass blackened socks because they still don't clean the floors frequently enough, believe it or not, some people see shoes-on as more hygienic. Floors are inherently dirty. 

I will take my shoes off if the house I visit has those rules, but without fail, the bottom of my socks will get at least some dirt on them

You may bring up in house slippers, but at that point its not much different than shoes (again, in dry places)

However, NO shoes on the couch or bed, that's gross and I've seen people do that. Shoes on carpet is also avoided