I mean that alone is a several trillion dollar a year improvement that will continue on indefinitely, and that's only one of the many applications for blockchain.
Consider that roughly 75% of American adults of working age are either unemployed or underemployed, and in most countries it's vastly worse than that. The reason most of them are unemployed or underemployed isn't (for the most part) that they're unable or unwilling to work or that they don't have valuable skills, but rather that double entry accounting doesn't enable a broad enough spectrum of economic relationships to capture the long tail of human talent.
When I say this is going to be a multi-quadrillion dollar technology I'm not kidding around. 99% of the stuff you own today wouldn't have been possible without the invention of double entry accounting, which vastly expanded the types of economic relationships that were possible and thereby vastly expanded the types of goods and services that could be produced. DLT isn't a replacement for your MySQL instance, it's a replacement for double entry accounting, and a 10x improvement at that. When people look back 500 years from now they're going to see that the vast majority of the (then) modern world wouldn't have been possible without it.
It's going to largely replace the middle class in the same way that automation has largely replaced the working class, because if you go down the Bureau of Labor Statistics list of jobs it's pretty clear that most middle class American jobs are basically just fulfilling glorified accounting functions.
Even just considering supply chain, as the profitability of creating counterfeit items decreases that doesn't just reduce the percentage of things you buy that are counterfeit, but it also makes it possible to make entirely new classes of (genuine) products that wouldn't have been economically viable previously.