Let's agree on a definition first: web 3.0 is using blockchain tech to replace current server-side computing (static file hosting, functions/processing, databases, etc) and online centralized services (payments, identity, etc).
So, is it bs? No, it is not. If you are a developer, you can go now and build a dapp (a web3 application or distributed app).
So far so good, but:
A simple dapp will cost cents to host/run (even better: will cost only once!) but, can it scale? How easy/cheap would be to run a big, very big, social net? An online store such as Amazon? Uber?
No "password-reset" mechanism. That just sucks.
Keeping the current web safe for your uncle is a pain, yes, that uncle that clicks on every link sent from the rich African prince. Imagine keeping it safe once you help him install a chrome-ext crypto wallet so he can login and consume content from a dapp social net?
It is not really decentralized: you public facing dapp cannot be directly served from the nodes of a blockchain, you need a gateway, that is a centralized web server (good luck making SSL work for your registered domain!).
It would take many years for businesses to migrate/adopt web 3.0 standards. We are barely finishing moving tech to "online versions" from traditional client-server apps.
Miners are businesses, running nodes costs money, they ought to make more of what they spend otherwise they will just disconnect the node. Your data/code may be distributed but its persistence/availability depends on the economic success of whatever project you choose to trust. Early adopters of web 2.0 server-less apps experienced this first hand when they had to port their projects from Parse to something else when FB bought it and shut it down.
Professional miners are needed. You are not going to build your banking dapp on the spare capacities of our laptop's hard drives and CPUs, or are you? Might as well trust the engineers at Google or AWS who have it already figured out and are charging reasonably for it, no?
In sum: web 3.0 tech is here, it is interesting, but it is not a hammer for every nail.