Product cannibalization against innovation

Product cannibalization is that fear that keep big compnies innovate with new products because with the old products the profit and cost are clear with less uncertainty while innovating include risk and lot of incertitudes.
So many things was planned to be doable so many years before they touch the market. If it’s from someone like me who care? but from big corporations this is not acceptable. Realising innovation is something we should legally impose to corporations why are they keeping all these amazing projects on shelves and keep always their eyes on profit and stock prices.
Innovation as obligation. An innovation score is something interesting for judging a company. I dont know how it could be implemented fairly and precisely.