There is value in a Masters because it introduces a new mode of research beyond the bachelor (self-directed investigation vs. learning by rote).

The downside of the Masters is that it is a degree without role. It doesn't qualify you for anything more than the bachelor does (e.g. grants, faculty positions, entry to certain "degree conscious" societies, etc.). Those things don't matter in a lot of cases but the incremental time cost is so small that it would seem worth it to do a PhD instead.

Your PhD really shouldn't take 6-7 years. Realistically, the Masters should cover all your course requirements so the incremental time should be 1-2 years. If that's not the case then you have a time management problem which is a major problem for any contemplated entrepreneurial activities as well.

Definitely. A Bachelors gives you the foundational knowledge in a field. A Masters should bring you up to the level of the current research. A PhD requires you to create new research.

A Masters degree is a great way to get the background to understand current research without the time investment of a PhD.

(Or do a PhD in the UK - 3 to 4 years is normal)

Depends on what you're trying to do. If the technical skills you acquire with the degree are useful for the business, then of course yes. If not, then of course not.

You should also be aware that not all masters degree classes will be relevant. You could acquire the relevant skills through some non-degree-seeking classes.