Recently a talk was given at a local association and clearly the presenter felt a need to be dramatic (at the very least). The initial statement was that Regression Testing was bad now and would only get worse. Under two current methodologies (listed below) that is the case:
1. Continually add to the regression test base and retain all that is there. The ‘more is better’ approach. Eventually the regression base grows too large (as happened to a client of ours where the regression test for the release every quarter occupied several people testing for the entire quarter and took more than a year of resource time to complete) and thus takes an increasing share of the testing budget to the exclusion of useful testing.
2. Ditch the entire base when it is felt that it is no longer providing any benefit (has not found anything new for several releases) and either start with a new base or forget about regression testing.

Either of the above approaches are expensive in either resources or risk – take your pick.

The correct way is to make sure that the regression is planned and organised to serve its purpose which is Risk Reduction commensurate with outlay.