Thanks for your message, Martin.
I am not sure I understand what you mean when you ask whether DeFi is a thread for incumbent financial and tech dominants. DeFi is a way for new entrants to disrupt the currently centralized financial sector. So it should, in principle, weaken the market position of incumbent financial firms.
Irrespective of what we see in the current bubble, assets should always be valued along the same model - based on future cash flows. But in a bubble, investors are prepared to accept more aggressive assumptions regarding future growth and market potential. Hence the higher valuation multiples we see at the moment. Some of these assumptions will be seriously off and will lead to a market reassessment at some stage. We will have to wait till central bankers stop flooding the economy with free money before that correction can occur.