What is more likely to happen is that balances in 401(k) accounts will be used for various accounting and tax calculation purposes in the future -- and effectively has the same impact of "confiscation" in a back-door kind of way. One big one that comes in mind involves future Social Security payments to retirees. I can easily envision a day when Social Security benefits are partially reduced for responsible retirees who have substantial assets in private retirement accounts (401k, IRA, etc.).
I also think anyone who did a Roth IRA conversion in the last ten years and paid the income tax on that conversion was a fool. I am almost 100% certain that those Roth IRA accounts will not remain "tax free" into your retirement years.
I agree. Taxes later is ALWAYS better than taxes sooner.