The real issue with the 1994 Crime Bill does not seem to be the Three Strikes law, which had a trivial effect on incarceration, but with the Truth-in-Sentencing (TIS) Grant Program which encouraged states to adopt truth-in-sentencing provisions and provided funds to deal with the anticipated increase in prison populations.
Here is what the TIS Incentive provision was about:
Title II, Subtitle A of the Violent Crime Control and Law Enforcement Act of 1994 (“Crime Act”) (Pub. L. 103-322), established the Violent Offender Incarceration and Truth-in-Sentencing (VOI/TIS) Incentive Grant Program. The program assisted states in their efforts to remove violent offenders from the community and encouraged states to implement TIS laws. Originally administered by the Office of Justice Programs’ (OJP) Corrections Program Office (CPO), the program was transferred to OJP’s Bureau of Justice Assistance (BJA) in November 2002 after an OJP-wide reorganization merged CPO with BJA. (Source)
The Truth-in-Sentencing provision distributed nearly 2.7 billion dollars to the states, most of which went to the expansion of the prison system.
The True Impact of Federal Three Strikes was minimal.