There is actually a hell of a lot that prevents the Lochner-type case from becoming law. First, one of the major recognized problems of the case is that it was decided the XIV Amendment grounds of liberty. The Supreme Court in the 1920s and early 30s struck down many laws on this basis, frequently New Deal legislation. However, for the past 75 years the Court has applied a rational basis test to determining these cases involving economic cases. Therefore, precedent has established review of these cases on a standard that the law is constitutional if there is a rational basis for its enactment to achieve a legitimate govrnment purpose.

If you understand the process of certiorari, you know that a miniscule percentage of cases seeking SC review actually are granted review. It is rare that a case, like Lochner, that does not involve a fundamental right, and had been decided by the Circuit Court according to the low level of scrutiny, firmly established by decades of precedent, even makes it to the SC for consideration (4 justices need to agree to accept it). Through stare decisis and the application of tests for review, it is highly unlikely, you would see Lochner reborn in this day .