Despite Congress' general dysfunction, this seems like a problem that could feasibly be solved. It would make most Congressmen of both parties look good to pass a bill that e.g. restricted sitting members to index funds/mutual funds/etc.
A new "boutique" mutual/ETF would spin up overnight which included just the assets already being insider traded.
Even that is open to massive bias. Who would vote to curtail the 7 tech giants when their own portfolio is basically the SP500 those companies dominate?
Great intention, but too simplistic. The lawmaker has a third party set up a trust for the benefit of his children and the trust owns a company in yet another jurisdiction that just happens to not only take a position in a certain stock, but probably provides "consulting services" for a healthy fee. And that is the simple version. By the time the lawmaker's interest is fully obfuscated, the legal structure is fully compliant with every letter of the law, just not the intention. Better to have fewer laws that are actually enforceable.