peeples....There are hundreds of potential opinions on this, I'm sure. So much of the answer, depends on available "space." Let's face it, if individual rooms is not even possible, this is a non-issue....or it requires an entire, involved plan to move, add-on or make some sort of major change.
IMO, it also depends on the age and sex of the children. Until ages 5 to 7, sharing a room seems perfectly fine and may even be preferred by the children themselves. The vast majority of kids don't especially like sleeping alone.
As kids get older, they may be learning to appreciate privacy and some solitude....a "sanctuary" of their own, so to speak. This is simply normal.
I see no danger at all of someone becoming "spoiled," because they were able to have their own room. I don't even see the relevance in that.
I can see of only one scenario that would make room-sharing a really bad idea and that would be a sister and brother after age 7. In this case, parents would have a serious responsibility to use simple common sense and courtesy, to provide their kids with separate rooms.