There are legit startups out there that do change the world. Most of them are not companies that you've ever heard of.
I think that companies that change the world satisfy the following criteria:
1 - their work is very hard to replicate. Not impossible, but it would take a competitor a long time to reproduce their product or service.
2 - people would notice a tangible impact on their life if the company disappeared tomorrow.
We won't know which small startups right now are and aren't until several years from now.
All of the big cos right now that have changed the world were a startup not long ago. Yes, not all of the startups will succeed, but there will be yet another trillion dollar company some day which is today somewhere in the realm of early stage startups.
How old and how large has really nothing to do with being a startup or not . It just means a fledgling business whose revenues are expected to change rapidly and is developing a product/ business .
This is in contrast to stable or blue chip like companies who have stable revenues and their product lines are very well established.
The distinction
is important for two groups of people .
a) investors - Risks and rewards are fundamentally different , therefore valuation methods are also different t you would use something like a Discounted Cash flow for stable corp you might look at IP, ARR , DAU or any number of other metrics for a startup whose revenues are not stable enough to use DCF etc
b) employees - change or innovation is far more deeply grained culture in startups , What worked yesterday may not work today, that requires different mindset to be successful at
Amazon , Uber are still startups despite what you think about their sizes , ages and current revenues . Building a AWS is only possible if you can completely rethink what is that you sell .
That sounds very exciting. Can you point to one startup that's changing the world?