Megacorps can move faster than you think.
It's a common trope in the startup world to assume that the Googles and Microsofts of the world are incapable of moving quickly and building game-changing products. Despite how often people say this, it's simply untrue.
The issue is not one of ability; it's motivation. A large business isn't going to change course and divert resources into something new unless it sees a strategic reason to do so. They aren't going to re-invent existing products until they have substantial evidence that they are leaving money on the table. However, they are quick to abandon ship on products that don't "Move The Needle"."
This leads outsiders to conclude things like "Microsoft can't do cool stuff."
The Reality
This line of thinking completely ignores what happens when a large corporation does find a reason to change course. For example, a few years ago, Microsoft got serious about extending its claws into the developer ecosystem. Not only did they buy Github, but they also built the most popular text editor (for software, at least), VS Code. But that wasn't all; they went even more extreme.
Microsoft built a competitor OS, Linux, directly into Windows via WSL.
Microsoft decided to rewrite reality, and within three years, all three game-changing products were live. Look at the timeline and imagine a small, scrappy startup pulling this off.
On April 29, 2015, Microsoft released VS Code, which enjoyed immense popularity. The next year, on August 2, 2016, WSL was released. They were working on these tools simultaneously. Less than two years later, after seeing the new tools and strategy succeed, they bought Github on June 4, 2018.
Even ambitious startups don't dare to claim they will own the world's most popular editor, a transformative tool that turns one OS into another for work, and the world's most popular code repository.
Of course, the story didn't stop there. Microsoft continues developing each of those projects today. WSL2 is out, GitHub works much better with repositories of crazy size (such as Windows itself), and VS Code has been getting frequent releases and features ever since it launched.
This is what it looks like when a Mandate From Heaven comes down from the top of a trillion-dollar business: "We will own this category; now go and make it so."
All Is Not Lost
None of this is to discourage startup founders or imply that you shouldn't pursue a business idea you believe in. It's only to give a bit of a reality check. There's still plenty of room to compete as a startup. Startups can focus and iterate within a specific domain in a way that doesn't make much sense to the big guys. For a giant, if it's not strategically important, it's probably not worth doing at all.
So, go build your business and make your millions. Pick something you're passionate about and create the perfect solution that no megacorp analyst would consider as a proposal. Just don't pretend that tiny startups are magically better than the kings of capitalism. If you're a Gitlab (Started in 2011), you might discover that your biggest competitor is suddenly a Trillion-Pound Gorilla.