* environmental impact can (and is being) addressed technically. Bitcoin doesn't even have (Turing-complete) smart contracts and web3 can exist without it (or PoW in general)
* lack of regulation isn't the tech's fault, and is also being addressed
* consolidation of authority: agreed, that is critical. But it's not worse than the current web. A handful of players can decide to effectively take down any project, and that also happens. Web3 does not fix it to the extent people claim / hope because of this concentration, but it's not worse
* impact of NFTs - What do you mean? Most NFTs are just hyperlinks that provide very little in the sense of uniqueness of whatever resource they're pointing to, I agree. But NFTs can be implemented differently, and anyway, the existence of problematic use cases doesn't negate other use cases.
Re: environment being addressed - is it? I have yet to see any actual evidence it's improving or that it's going to with reasonable assumption. The only thing I've heard are assurances. Can you point to a mainstream source (or project proposal)? All I have seen is that it scales WAY faster than traditional finance and that the increasing blockchain useage is incentivising oil and coal plants in China and Russia. These seem pretty damning. Proof of Stake doesn't help enough here.
Lack of regulation not being the tech's fault doesn't really make a difference. Its the same argument as 'gums don't shoot people, people holding guns shoot people'. The issue is still fundamentally about what to do with respect to the object the person is using.
Re the consolidation not being worse: hard disagree. This is measurably worse because there is now a second order of ownership beyond the usual social conventions established. It is an opportunity to financialise and gatekeep further. Additionally, those same big-player actors are not restricted from starting their own cryptocurrency or NFT related venture, then incentivising their userbase to do it. This is a common trick in software (a common example: Facebook or Uber and their app pop ups pointing you to their other apps). I think you are operating on the assumption that crypt I currencies are dictatorship-resistant, which I don't think reflects reality. There are lots of examples of cryptocurrency project decisions coming from above. A banal example: leader-led forking is not uncommon. See bitcoin and ethereum for popular instances of that.
Impact of NFTs: NFTs have a wide range of issues associated so this could be its own conversation easily, but the issues that come to mind immediately are the incentive to steal assets (legal ownership and blockchain ownership are not the same thing), lack of underlying value (as an asset, they're widely agreed to be highly risky for low expected return), their exposure to gas prices, the fact the hyperlink is the only thing 'immortalised' on the blockchain, meaning they're actually MORE fragile than regular assets in practical outcomes, 'gifted' malware that cannot be rejected, the architectural incoherence of smart contract apps, and many more.
Regarding the suggestion that problematic use cases does not negate positive use cases: well I think it depends on how good and how bad the respective cases are, and comparing that to the alternative of none of them. All of the use cases I've seen for smart contracts are either outright scams or at best very poor value propositions. I think this idea that 'the good should not have to capitulate to the needs of the bad' is somewhat adolescent and doesn't really reflect the real world. No one makes business decisions like this, even in software.
A more explicit refutation is this: if the people who participate in the community of the technology don't actually address the issues surrounding it, who should? Most people outside the community would say that the community should resolve the issue and any inaction looks bad, because it indicates a lack of social caution.
One last thing: I think its important to assess the intent behind project leaders. People like Vitalik B propose some very unpleasant uses for the block chain (he has on record suggested storing medical records on chain is a possible use - which is a very insecure and obtuse solution to the problem of internal medical record storage) and some very warped worldviews. Giving him control of a value mechanism seems bizarre at best as actively damaging at worst. Vitalik is not the only one with issues of course, but I would argue he's the most influential, next to maybe Musk (who I shouldn't need to explain why he's questionable). His attitudes should be more carefully scrutinised by the community.
* lack of regulation isn't the tech's fault, and is also being addressed
* consolidation of authority: agreed, that is critical. But it's not worse than the current web. A handful of players can decide to effectively take down any project, and that also happens. Web3 does not fix it to the extent people claim / hope because of this concentration, but it's not worse
* impact of NFTs - What do you mean? Most NFTs are just hyperlinks that provide very little in the sense of uniqueness of whatever resource they're pointing to, I agree. But NFTs can be implemented differently, and anyway, the existence of problematic use cases doesn't negate other use cases.