While I'm not really technical and cannot provide you specifics, I have read countless of times why this DeFi thing is full of flaws to the point that they're all but decentralized. The great majority of them have central points of failure. Proof of which is the massive number of so-called DeFi platforms that ended up hacked or being exploited. Billions and billions are lost because they're fake. That they are severely criticized for carrying the decentralized label is certainly justified.
What type of demand are you talking about and what types of platforms of the different kind will take over?
The demand for Bitcoin would have probably remained high despite centralized platforms like FTX, Binance, BlockFi, Celsius, Voyagers, 3AC and the like not approved for operation.
If only centralized exchanges didn't become a thing, we could have better ones. DEx could have been the thing. So if centralized exchanges would perish for good, DExes could take over, or anything that would at least sell buyers with real Bitcoin and not just fake numbers.
I also agree with Defi as not being 100% decentralized. I reckon the classification called Defi is a wrong. It should be called open finance.
Whatever you call it, but not decentralized, because they're not.
Let's not measure how much is lost by whichever. They're both bad apples in the market. They both should be avoided. They're both losing people's money. Fake decentralization is no better simply because centralized exchanges lost bigger within the year. Last year alone, DeFi lost north of $10 billion.
Development is never discouraged. It's just that standards are set high.