Ah, thanks for the info. Could someone explain how broadcasting options work? Shows that air constantly (Hunter x Hunter/One Piece) vs seasonal. Did JoJo take the seasonal route because the chapters are monthly?
For late-night anime the sponsors pay just short of 400-500 million yen per cours, several months in advance, to run their anime as an infomercial in the Tokyo TV market. A good rule of thumb is that "national" coverage - not actually national, just tagging on the Osaka and maybe Fukuoka/Sapporo, plus random mini-markets - doubles this outlay.
This can be mitigated by TV stations sponsoring the shows, at which point their contribution can range from a partial discount all the way to free time plus. Conversely, daytime slots are horrifically expensive if they're even for sale and even a FMA or a Madoka relies on TBS or MBS sponsorship.
What this means is that, if the sponsors aren't confident about being able to resell \1b of commercials during 12 eps or turning \1b more profit off merch than they would otherwise, the slot doesn't get bought. Sponsors are willing to experiment for a cours, maybe two if it's a popular franchise, but beyond that you need to show results before they'll stump up that cash to buy the airtime (which is by far the single biggest production expense - actually animating, dubbing, and recording the show ranges from \60m a season for complete sideshows, to \120m for the "average" low-budget title, to around \500-\600m for a complete budgetgasm giant robot blowout. JoJo was probably around that \120m figure for each cours.)
Edit: Oh, and to clarify if you hadn't heard the terms before: a "cours" is a 3-month block of episodes that Japanese TV stations like to book their airtime in, running between 10 and 13 weeks depending on which holiday specials preempt pieces of it. A "season" is then usually used to refer to chunks of cours purchased at one time: JoJo has had one season so far, which ran two cours and covered two arcs; the next season will cover one arc and is expected to run 2-3 cours.
