Re: Showtime Singer Gig Won't Start?

@XCoco_LolipopX  Did your sim change into her career outfit?  If not, that could have been the issue, and you can force her to do so if necessary by clicking on her and selecting Change Outfit > Career.

Another common issue is that the venue's proprietor doesn't show up.  If you're not sure who that's supposed to be, just hover over the name of each sim near the stage; the proprietor sim will have that listed after their name.

If you use mods, particularly NRaas MasterController, it can help to reset the venue lot a couple hours before a show is supposed to start.  I realize that part of your complaint is that EA never fixed this issue, and using a mod to do so doesn't really address that.  But the game is what it is at this point.  I personally think that even if the performer careers didn't work at all, which is not the case, Showtime would more than worth the pro-rated sale price for the collection on Steam.  But if you're frustrated with it, there are many other things for your sims to do and learn that more or less work as intended.