I suppose because modernising existing systems is tedious, error-prone and expensive. The latter two in principle apply to implementing new systems as well but

I suppose because modernising existing systems is tedious, error-prone and expensive. The latter two in principle apply to implementing new systems as well but at least those are exciting and, well, new. You'd be hard-pressed to find a single company that relies solely on digital processes. In terms of digitalisation everyone seems to be talking about AI, AR, robotics and technologies like Blockchain. However, while certainly interesting those aren't the main avenues for bringing about digital transformation. Replacing paper-based processes and doing away with the need for physical presence to conduct business are. So, Walmart will soon have robots running up and down their aisles while at the same time we still largely rely on paper for invoicing and accounting. We'll soon have self-driving cars for all our wonderful commuting but we still haven't figured out how to use technology for remote working to make travelling to a ridiculously expensive place called 'office' a thing of the past.