We are a LONG way from running out of numbers. It's not the NFL where you need 50+ numbers for a team. It's fine if 10 or so are unavailable. There are still numbers that nobody has worn ever in Avs history.
To me it has a lot to do with honoring the Cup winners. Since that will pretty much dry up after Hejduk it's not a concern of mine there are too many.
Being a long way from running out of numbers isn't the point. The point is EVENTUALLY it will happen should the NHL and Colorado Avalanche continue to exist, so there's no reason to retire numbers if they can be honoured.
There's nothing worse than seeing a team full of weird, high numbers. Look at Montreal for example:
1, 2, 3, 4, 5, 7, 9, 10, 12, 16, 18, 19, 23, 29, and 33 are all retired and unavailable to be worn. Almost an entire team worth of numbers unavailable. Obviously a different situation since they've been around for 100+ years but the point is why retire the jersey when it can simply be honoured, go into the rafters, and then someone else can wear it.