Retirement accounts are not intended as general purpose investment vehicles. If everyone could put their 401k/pension in anything, you would see a lot more people getting scammed and gambling on the latest GameStop internet mania. If folks want to invest like that, get a brokerage account. If you want tax-advantaged retirement planning, being limited to less risky things is the tradeoff you make.
There's nothing stopping you from having both at the same time, with the caveat that your contributions to the IRA may not be deductible if you earn over a certain threshold.[1]