There are tons of strategies out there that does not involve insider trading or fraud. One such example is simply shorting Bitcoin at the market open whilst going long QQQ. This has paid a lot , like today , in which Bitcoin is down 3% and QQQ down a tad. There are people running this strategy now which despite being public knowledge, is still profitable. Shorting bitcoin during market hours, in fact, realizes all of the downside of Bitcoin without the upside from shorting it.
There are other strategies like this. now imagine you assemble the greatest minds in the world and tons of computing power to find many strategies and run them 24-7.
Beating the S&P 500 is difficult and there are now zero fee funds to mimic it.
The cause? Someone, somewhere in their financial product chain was not being faithful about the volatility of the asset they were basing their whole model on so when the market went tits up they did to.
Insider trading exists but the amount of secrecy to make that theory a reality would be unobtainable.
Why would they involve their spouse? If it was illegal for them to trade but their spouse made a trade it would be trivial for the SEC to trace it back to intel they learned.
You are right that enforcement is weak, but that is not because it is legal. The notion that members of Congress can legally trade on knowledge derived from or used in the performance of their duties has not been true for over a decade at this point.
No congress can trade on insider information full stop
https://blogs.luc.edu/compliance/?p=4459
> Simply put, insider trading is illegal. But, if you are a member of Congress, there is a loophole. Members of Congress and their families are allowed to trade stocks with almost no limitations. There isn’t a limit on lawmakers trading stocks based on classified information nor is there oversight regarding the trades that lawmakers are allowed to make based on other information they are privy to as part of their job. This is in glaring contrast to the strict insider trading laws that ban the same kind of behavior of everyone else in the county.