You can consider it, sure. It happens, and it's a risk for many companies. But keep in mind this doesn't usually happen unless you've gained some kind of traction or product-market fit (tech giants have other things to do and will only take notice if it's worth noticing).<p>Does this mean if you make something good you'll die? It depends - on the industry, and the product or service and the nature of your IP.
Just assume that the tech giants will copy you, and figure out how to execute better than they can. Google created Google+ to compete with Facebook, look how that turned out.Google has tried several times to build a great smart phone.
Don't worry about big tech companies, worry about nimble startups trying to copy you. Just build a better product, and build it first.