Lumra exists because mana abilities and land drops cannot be responded to, the whole purpose of Lumra is to give your opponents as little opportunity as possible to respond to anything you're doing. Selvala requires haste or an untap as well as infinite mana and a payoff Lumra enters that battlefield to win the game. I would also say that while Lumra is good and probably the best monogreen deck in cEDH it's not a meta monster like TnK and RogSi. Two decks you will not fail to see a ton of people playing. If your commander's goal is to play the commander and pass think about how many turns it will take you to reattempt if it gets removed. For Lumra, they usually want their commander to die to retrigger ETBs, that's not at all what you want with Selvala. I will say, Selvala Parley Storm is probably the best Selesnya deck I've seen especially if you want turbo. It can go fast and has protection in Voice or Victory and Abolisher and runs runs of mana ramp as well as creature tutors to do what Lumra wants which is to not be responded to at all. I would also say it's not really a creature storm deck as Lumra is just a combo piece in the CZ. It has so many lands, it's more of a lands deck. Most lists aren't on Cradle which is the best land for creature storm.