Excluding the U.K. and Ireland (tax haven) the difference between the EU and U.S. is greater, but (eyeballing) only on the order of 30-50%--e.g. ~4% vs ~6%.

What's more surprising is how small the share of GDP is the digital economy in the U.S.

That said, "digital economy" may be a poor proxy for understanding the impact of privacy regulations. It's a superset of tech industries, including much more than those parts which broker private information and to that extent would overestimate the impact. OTOH, I presume "digital economy" excludes large parts of non-tech industries (i.e. traditional sales and marketing companies, TV and newspaper ads, etc) and thus underestimates the potential impact.