LOL...this is not an uncommon occurrence.
Inventor's have read the archives of the experiences of inventors, who have created disruptive technologies, only to be usurped by the firms for whom they worked, or by others with deeper pockets and powerful contacts. The Ford inventor who invented the modern day windshield wiper is a notable example.
But those days, with few exceptions, are long gone.
I tell inventors to protect your tech as much as you can and in every way that you can. But at some point, your idea dies on the vine until you share it with critical advisors who can actually assist you to bring that idea/tech to full manifestation.
You really don't have to worry about anyone, to whom you should really be concerned, about stealing your idea until you are wildly successful!! Wildly successful!
The entities that you should worry about will not dedicate the time, money and resources to intrude in your space until there is a clear, validated reason to do so. By that time, you have had protected yourself, had an aggressive launch, branded yourself in the marketplace, and all copycats are just that...copycats.
At that point, just focus on innovating and being true to your market...and frankly, just be willing to compete.