To get around this sometimes two filters are used, the second filter helps the first one to be more efficient. Using two filters usually increases the filter factor, however. The reason that interference filters are used is that they can be made to such demanding specifications. Costs for interference filters have come down in the last few years. They are very affordable.
Interference filters have some draw backs.
They can't be cut down for size. They also like to be cleaned very gently. Stained glass filters are still used in a lot of applications such as near-UV filters and routine use blue filters. Even here the interference filters are making inroads. Nikon makes an interference blue filter that is a real joy to use and Olympus makes an interference green filter that I have always used for black and white film and tv.