[anon8418]

How many launches has the Soyuz had?

Think how many more cycles a plane goes through a day / month / year / decade. Times that by the number of models of that plane out there.

[rohit89]

A plane doesn't undergo stress anywhere near what a rocket goes through and we understand all the science behind it very well.

[bduerst]

It's a different class of stress - think marathon vs. sprint.

[jessaustin]

I doubt any spacegoing rocket will ever be expected to match the durability and maintenance schedule of e.g. the average 767.