I wonder you are talking about being choosy and selective when deciding to invest because not all defi projects are fake or scam because of the open ecosystem and also defi has big role to plwy in future financial sector. Yes you are right that only small percentage of projects will dominate while others will struggle or fade away.
I think what he meant is that people are crazy about DeFi projects and investing without doing some research or even understanding the project and in my opinion that's what happening nowadays and yes, only small amount of projects gonna make it long term and the rest probably fail mid-way so that's why people need to invest wisely to pick the best of the best projects.
People are really into DeFi project probably because it always give profit but its not gonna be like that forever.
Today, the first serious scams on the market of defi projects began. You can Google about the Yfdexf Finance project, whose developers raised $ 20 million and disappeared with the investors money.