Working with centralized technologies is much easier than working with the blockchain. Additionally, web3 is not very advanced for its costs. Needing to pay money (even a fraction of a cent) to do basically anything is not a compelling model, especially considering that most of the “fast” blockchains still take a couple of seconds to do anything.
I definitely phrased my original comment wrong. Cloud providers do charge for basically everything. However, the charges are much smaller that fees on most blockchains. ETH gas fees are a good example of what I mean, although they are absurdly high compared to other blockchains.