Every special relationship needs time and care
Every relationship needs to be given its due. Our relationship with our parents is probably the most selfless one. And yet, the onus is on us to make the relationship special and rewarding. We just can't take them for granted and say, that they will accept us no matter what our avatar.
If we share a special relationship with our sibling/cousin then we should make time to catch up with them for lunch/dinner or make time for a holiday together. When we say things like - life moves on, people grow apart or there's no time; these are just lame excuses. There is always time, if we want to make time. If we want to make our relationships count, we will always find time for the people who matter.
I basically have a problem when one relationship supersedes every other relationship in your life. Life should be about finding the right balance and not about making relationship choices where old ones always have to make way for the new.
The reason we give so much importance to friendship is that when people/situation/relationships around us change, there is this special someone who remains our rock. If that bond is in a state of flux then either your friend doesn't have the strength of character to remain consistent or the relationship was never worth your while.
In a perfect world, we would have perfectly selfless relationships where we would just give and expect nothing in return but our world is not perfect. A famous quote on friendship from A.A. Milne's Winnie-the-Pooh goes like this:
Piglet sidled up to Pooh from behind and asked. "Pooh?" he whispered.
"Nothing," said Piglet, taking Pooh's hand. "I just wanted to be sure of you."
Sometimes you just need to be sure.