How do you forecast a five year roadmap?

3-Years are more realistic these days. The landscape changes faster than it used to and you have to plan in shorter time-frames to be agile and nimble in your approach to product, tech, security, etc..

I have not seen a five year roadmap in the product, or tech. It is so far out to predict what customers want, or even the tech to use to meet their needs. We build 1-2 yrs product strategy, 1 yr roadmap and 1-2 yr tech strategy, with some overarching ambitions

This is more of a projection than a solid plan. Include a range of possibilities and multiple potential outcomes.

Basically, I follow a common process of: assessing current state of our technology, reviewing current business needs plus pipeline ahead and then checking on new trends on the market to finally prepare a roadmap for the department.

Yes, like many large enterprises we do have five-year roadmap; however, the key to the success of these roadmaps and strategies is its ability to adjust and adapt to the market changes