Let's take your argument point-by-point. Let's take the US perspective to start.
a.) You start a business in California and plan to do business that involves EU customers. If you plan on making actaul money you'll hire a lawyer for a reasonably small number of hours to incorporate, ensure you have trademarks covered, get your EULA in order, vet your corporate structure, etc. GDPR is just another thing to add to the hopper--it probably adds an hour or two to the whole process since legal procedures are pretty template driven. Most of the cost will be the lawyer briefing you on what to look out for. (Based on my admittedly quick reading of GDPR summaries.)
b.) There's already a net decreasing trend in startups in the US, but it predates the GDPR by many years. [0] If you are looking for culprits in the legal system you are far more likely to find them in US laws (or lack of them) than anything from Europe.
Taking the EU perspective, well, I've run a small tech business in France and GDPR seems like noise level compared to the other regulations you need to deal with there. (Hiring and firing being the biggest but there are others.)
[0] https://www.nytimes.com/2017/09/20/business/economy/startup-...
Edit: add source