Correct, we don't need centralized speed.
At least there's one reasonable, critically thinking individually poking their head up in the thread.
Pro-tip, when you want to post twice in a row like you just did you can easily Edit the first post to include what you would've made the second post. That way things are less messy.
Bitcoin has been determined as semi-decentralized due to the big miners out there controlling most of the network, and the fact that it hasn't receives rapid development, it might be much harder to update a decentralized protocol than we think.
By that logic there can be no true decentralization. The decentralization will become broken down to some extent if you analyze it based on inequality of hash power among miners. At some point, unless everyone is running an equally powered mining rig full-node then the best we can hope for is semi-decentralization without a radical change in the foundation. Even if everyone was running an equally powered rig, we would also have to somehow nullify any influence that someone may have over miner(s), because this could be abused as if the power was the influencers, if the influence is great enough.
I might be going off on a tangent, but my point is this: Even if we agree that Bitcoin is only semi-decentralized, then it would still be a better option than anything centralized. Harder to update, because of the requirement of consensus among the development community in my opinion has kept Bitcoin healthy all these years.