The Life Expectancy of Glass Curtain Walls

Glass curtain walls have a 25 year life expectancy, according to an engineering firm. The glass itself doesn't fail, but the sealants that they were using in the late 20th century just have a 25 years life expectancy. Is there any sense of who's liable for this anymore? I think they'll have a job going back to the original building designers and materials suppliers. It all gets very, very complicated.