Everything that isn't consumer electronics has longer lifecycles. B2B customers aren't as flexible: it's not a question of throwing out your smartphone every 2 years and buying a new one, as soon as your action is multiplied across 1000+ devices everything takes much longer. You might spend an entire year doing the national rollout, and once you've done that you don't want to do it again if at all possible.
If there's any kind of qualification, tracking, auditing, or compliance issue everything will take much longer again.
I'm not sure this is true. I see plenty of products that have 1k+ rollouts more frequently. Maybe some businesses aren't sophisticated enough to do that, but those are the large, slow businesses of the herd that will get picked off by faster movers. That's why healthcare, defense & education are popular industries to enter right now, because many of the entrenched players can't keep up with the game. There is _no_ intrinsic reason that b2b should be different from b2c. I bet the old guard's lobbyists and capital can only last for so long.
If there's any kind of qualification, tracking, auditing, or compliance issue everything will take much longer again.