I've been mourning the dearth of composability in DeFi at scale for quite a while. At some points, I've been thinking sharded/rollup systems breaks the money lego system too much I'd rather have quasi-decentralization but full composability to truly see the machinery at work.

But because of how fees work, a beefy non-sharded chain probably wouldn't be viable, if we think about the vast scope of different activities "the future of finance" would encompass: auctions, oracles, DEXes, domain sales, derivatives, arbitrage, NFTs, gaming, whatever.

If a monster DeFi-capable chain gets sufficient traction and actually becomes "the future of finance", then demand for block space/gas for its service would pretty much be infinite, and for each category of activity, there'd be different minimuns people would be prepared to pay.

The people who would pay most for transaction inclusion would probably be the financial sector (trading spot, derivatives etc) and with HFTs, MMs, algo-traders, the demand is literally endless. There will of course be a cap, even on this monster chain.

But in a permissionless system, the devs, the degenerates and professionals in finance will use all of it. The more space you give them, the more apps they'll deploy, the more trades they'll do. The highest-leveraged traders will set the minimum fee for everyone.

So you think you can hardcode the fees, but this doesn't actually work, for 2 reasons:
1) without a way to win priority, the system breaks. One day, system is spammed, an important oracle call doesn't make it before deadline, everyone dies.
2) bribery will happen off-chain anyway

So, really, I don't think there's going to be a one-world-computer-fits-all. There will be different tiers of activities that will compete for transaction inclusion among other moderately similar price-sensitive users.

That means that *this* tradeoff probably doesn't exist, at scale:
- A high-through centralized DeFi chain with always low fees and full composability
- A low-throughput decentralized DeFi chain with always high fees and broken composability

Probably, it will be more like this:
- A high-throughput centralized DeFi chain with segregated composability based on different activities
- A medium-throughput decentralized DeFi chain with segregated composability based on different activities

I changed "low" to "medium" on the second alternative in that tweet? That's because if you break composability, you do get more throughput.

Thanks to how rollups work, the decentralization sacrifice you have to make to reach from a low to a medium throughput--

--Isn't nearly as bad as the decentralization sacrifice the monster chain had to make to go from medium to high throughput.

And then, the ironic/annoying thing is that they still couldn't keep cross-sector composability.