Why are traditional banks against defi when it benefits them too?

I don’t get why traditional banks are so afraid of cryptocurrency’s innovation. I think they should consider it as motivation to better their services and give people who use their banks a better opportunity to control their finances. People’s buying power declines by default. Fiat money stored in banks is tied to the monetary system, which can be devalued by inflation and currency debasement. So, if you put $100,000 into a bank account at the start of the year, and United States dollar currency debasement is 10% for the year, then by the year’s end, your savings can buy 10% less than before. (Source). Banks are just showing how greedy they are at this point. If they adapted to defi it would only benefit them in the long run.