Ask HN: How to raise 10M for a SaaS product?

The market structure an obsolete leader (lead time for highly requested features literally 6-10 years)owns close to 50% of the market. There is a large number of competitors literally none offer capabilities that would allow F500 company to switch from market leader to their offering. Building up a competitive offering would take a few years and a 10M round. This does not fit normal VC deal structure. How could one look for capital? (market size is about 6 billion)