I think it depends on the house. I have a large 2 bedroom house, 2 DC, 3 DSC and am currently pregnant with number 6.
The three girls share a double room, they are aged 14, 11 and 8. My daughter has the room to herself for the rest of the week. Also the eldest doesn't often stay overnight as she's with friends etc, so it's just the younger two. They have a bunk bed with a trundle bed underneath.
The bigger bedroom is split into two, me and DP are on one side (with new baby once they are born) and our toddler (18 months) has the other side, it's small but he only has a bed, some drawers and a few soft toys in there, plus he only sleeps in there ATM.
Our living room has a large IKEA room divider with a sofa bed for DSS who is 12. The divider provides alot of storage for his bedding, games etc and he loves having his own space downstairs where he can play the PS4 without disturbing anyone.
We also have a garden room- they all love it and are forever asking for sleepovers out there, it's got electrical outlets etc so I'm pretty certain we will eventually lose a teen to the garden too!
It might not sound ideal but it's working for us for now. Everyone has a space to sleep without it feeling too crowded. Lots of storage solutions help here. Hopefully we will soon be in a position to extend and create more bedroom space and an extra bathroom wouldn't go a miss either tbh, but for now it's fine, I love our home.