In this world, governments and big corporations might cease to exist as everything will be guided by both Blockchain technology and AI.
I don't know why big corporations would cease to exist. Bitcoin and other cryptocurrencies created a new market for big corporations.
For example, mining. You can't just make a start up company and start manufacturing a new asic or GPU, as those hardware are very complex. It is normal that two or three big corporations dominate that market.
Additionally, hardware wallets. We can already see 2 main companies manufacturing hardware wallets.
You can also see other big corporations in exchanges market.
Big corporations will not cease to exist...