The plumbing in the banking system still stinks but a new survey says bankers would like to do something about it. But, please, don’t rush them.

Luckily for the banks, consumers don’t have the nerve to stick ALL their money into the hot startups grabbing headlines everywhere. In fact, for all the hoopla around the mobile-first fintechs, millennials say they trust traditional banks more than the Venmos of the world. But that’s not the study we’re talking about. We are looking at the NTT Data survey of more than 1,000 consumers and 100+ bankers. The numbers say: one out of three consumers “would strongly consider switching primary banks for better online and mobile technology.”

Easy enough to say! Will those consumers actually go to the trouble of switching? Peter Olynick, senior practice lead in retail banking at NTT Data, says, yes. Fintech is now making its way past the early adopters toward mass adoption. Which means it’s time for banks to replace the aging pipes — an ordeal only 15% said they were likely to take on in the next three years. Which gives us a shiver of cognitive dissonance since 80% of US bankers say they “would like to modernize their core deposit systems.”

Fans of The Innovator’s Dilemma may well side with Olynick. True innovation takes root with the few (and new); then, before you know it, the incumbents are toast. The fatal flaw: The entrenched businesses spend their time and energy serving the customers they know (and are profitable) versus the unknown.

Financial institutions actually believe in the power of fintechs to steal customers. There are studies everywhere measuring just how scared they are of the innovators. However, banks face singular hurdles. They have many masters, known as regulators. They are trust-based institutions, loathe to make radical changes even when customers demand new services. Break that trust, and forget about millennials. And baby boomers. And everyone else in between.

This leads us to the current state of affairs in the backend of core banking functions — a rickety patchwork of superficial fixes. Olynick likens it to building a Tesla on top of a Model T frame. For now, banks have managed to make the systems work: Consumers can bank online or on their smartphones with almost any financial institution. But Olynick says the plumbing is a mess — ungainly and unlikely to withstand more tinkering. (Note: NTT Data is in the business of telling banks how to up their game.)

The survey says the expense of changing system is a major stumbling block — a classic reason.

But Olynick adds this re: Fear. Bankers worry about 1) “a decrease in security” and 2) catastrophic failure. It’s one thing for Delta Airlines computers to crash; another for a bank’s systems to go kaput.

So stay tuned for the next survey on As the Banks Turn. In the next installment, we will find out if they can beat the odds and overcome institutional and cultural inertia to do what they know is right.