They mean FPGAs I guess? They're certainly flexible but incredibly expensive for almost any purpose where a general purpose CPU or GPU could also get the job do

They mean FPGAs I guess? They're certainly flexible but incredibly expensive for almost any purpose where a general purpose CPU or GPU could also get the job done, and incredibly expensive compared to a mass produced ASIC that does the same thing, so they're always going to be a niche thing mainly for expensive low volume products.