So not just EU, but any other region in the world, like Africa, South America, Central Asia should just give up and not try to make a business that could disrupt existing giants?
They can, but OP's point is that a ban on US tech on its own will do nothing to produce a local Silicon Valley. It needs to go hand in hand with a massive push toward local entrepreneurial support, especially in places like Europe where the government exercises more control through legislation
I don’t think you really need to incentivize businesses. If people want to start a business, they’re going to start one, regardless of whatever carrot you throw in front of them. “I’d love to start a business and make a profit, but the government just isn’t giving me enough incentive!” - said nobody ever.