On average, you're right. But we're not quibbling about the average person here. We're talking highly skilled, highly educated professionals can expect at least a 50% gain in gross salary (nominal + exchange rate), face lower costs of living for goods and services, the aforementioned lower taxes and, critically, expect excellent private health care coverage that will likely cost less than whatever taxes are removed from Canadian paychecks.

If the choice is between very good private US healthcare vs. any Canadian public system, the outcomes and general healthcare service in the US are much preferable under most circumstances