Technology doesn’t get any closer to money-generation than in the marketing/advertising industry.
Back in 2007, I was building an ERP for a D2C client. The project was estimated in two years, with three engineers dedicated to it. The client asked the money question: what would be the ROI on this project?
We were clueless. How do you calculate the benefits of a custom-built ERP? The main motivation behind building custom software is efficiency. In raw terms, how much time this new ERP will save to human operators. You can translate time to money, and you know how it goes.
With AdTech/MarTech products, ROI math is much simpler. You are either making money or losing money.
Take, for example, MailChimp. If you have 50k subscribers, you will be paying $9.99/mo. Every time you send a campaign, you need to make at least $9.99, per month, to be break-even.
Add the software development costs to build a MailChimp type of platform (not sure why you would do that.), and then measure how much money you are making off the campaigns. That’s your ROI.
You can’t measure ROI in the same way for all the marketing and advertising products. However, you can measure them by how much money they are helping to make.