Lots of people I know have more than two bikes. Usually a road bike, a MTB or hybrid and a beater or two that probably hasn't seen pavement for a few years. But bikes don't take up that much space compared to other stuff as I'll explain later.
So for 5 people:
my garage
has 5 bikes:
2 hybrids
3 mountain bikes
1 thule cargo carrier for winter and summer skis, wakeboard, snowboards etc... looks like a coffin from StarTrek.
The basement has:
1 road bike (all the high end stuff stays in the basement)
8 pairs of skis:
4 are mine, all x-country:
classic style skis
freestyle skate style skis
a pair of vintage classic style racing skis
a pair of vintage wooden classic style skis
2 belong to one of my boys
a pair of downhill all mountain skis
a pair of freestyle twin tip skis
1 is my wifes x-country ski
1 pair of x-country skis that belong to nobody in particular and will most likely never be used again
many many sets of ski poles.. I've lost count.
an uncountable number of pairs of ice skates of different sizes and ages most of which should be donated to a skate exchange.
At least they don't take up much space
It's worse at my cottage up north where dockside on any given day, you'll see:
1 17 ft runabout
1 13 ft canoe
2 12 ft kayaks
2 different inflatable towables for tubing none of which are under 10 feet
2 wakeboards
1 pair of water skis
I had to put in a 12 foot dock extension on the side of boat dock for what is commonly referred to around the house as "the rest of the fleet". And I'm not alone. Plenty of people here have 2 boats.. usually an aluminium "beater" for fishing.
and my wife thinks that we can keep some bikes up there ? ? She was also pondering the purchase of either a kevlar and carbon fiber canoe or a kevlar and carbon fiber kayak...
and it's all in part to this lemming-like instinct that 40-60% of the residents of the Province of Ontario have to migrate north to cottage country on weekends between the May 24th Victoria day holiday (also known as May 2-4 after the ubiquitous cases of 24 bottles of beer) and Canadian Thanksgiving in October.
Now if I just figure out where I can safely store some bikes .....