FX are *way* under-counting. There are an awful lot more than 455 scripted television shows out there. Hell, there are more than that on YouTube alone.
Their mistake is to assume that something only "counts" as a TV show if it's in standard half-hour-with-ad-breaks format, and it's "broadcast" on something that they recognise as a TV channel. But a looser definition - say, "scripted video content released on a recurring basis" would include literally thousands more, and it's a bad sign for FX that they apparently haven't acknowledged this fact.
What FX are doing is the equivalent of an oil company not realising that they're in the *energy* business (and therefore subject to competition from solar power and the like), or a car company not realising they're in the *transportation* business (and therefore subject to competition from rail, motorcycles and so on). Or perhaps a better comparison is the phone company not realising they're in the *communications* industry, and therefore failing to expand into mobile and internet provision until it was too late.