Here's an HN comment I like to keep in mind when realizing a startup idea has been "taken" by someone else.
A while ago, I was in the same boat. Why try to recreate GitHub, or Uber, or Salesforce, or Facebook?
And once I discovered any competitors in my idea's field, I would chalk it down to "not worth trying" and call it a day.
But then I realized, if my town can have 3-4 Chinese restaurants with the same exact menus (probably supplied by the same exact distributors), and they've all operated continuously for over a decade....who cares about uniqueness?
Sure, none of these copycat places are raking in millions, but it's enough to support the livelihoods of the owner and all of his/her employees, so who cares? Your business doesn't need to be a unicorn to make you happy, as long as you're happy with that outcome.
Of course, tech does not operate the same way as Chinese restaurants, and for that I point you to Accumulative Advantage:
> Accumulative Advantage is when a small advantage at the beginning of something, such as kindergarten, becomes a little difference that leads to an opportunity that makes a bigger difference a bit bigger, and that edge in turns leads to another opportunity, which makes that initial small difference even bigger.
Put in context: You don't have to follow the same path your competitors did. Uber/Lyft poured billions into normalizing the concept of being driven by some stranger who uses the same app as you, so any new ride-sharing platform can spend that money in other areas. Giants like Microsoft have decades of technical debt they need to tackle; you can start building with 2019 libraries, 2019 paradigms (wouldn't the cloud have been great for startups ten years ago?) and 2019 performance. In order for the underdog to win, there first has to be an underdog. If you're brave enough to start, you may just be brave enough to win.
Another comment goes into why big companies usually won't compete with you unless you're a huge threat:
Also worth noting the downside of scale: some opportunities are "too small" for a Microsoft or Google to pursue.
Google revenue for 2018 was $136.8B. Extra effort to possibly address a small niche segment of a market, that would improve revenue by $1M per year, is too small to draw anyone's attention.
However, that same $1M/yr is enough to sustain a bootstrapped business and even possibly build the credibility to raise a larger round and try to win the space. If a company is already solving a problem, a better question to ask is "why didn't I know they exist?" It may be that they aren't properly tailoring their marketing to the target audience, in which case you have a clear opening.
Honestly, stop reading now and look at the full HN thread. It's worth it.