I've definitely had games with cultural victory without Rock Bands, if you are going heavy in national parks or seaside resorts, for example. Or just mass buying every great artist that comes up.
But yeah, I wouldn't mind seeing some alternate victory path option for some of them. Whether that just be alternate ways to produce works in the modern age and an increasing cap, or some fully alt way. Like I could see them simply add in a setup where each Opera House you build produces a "Great Work of Music" every 10 turns, and then the modern victory would be 20 total great works. So at least if you don't want to dig up the lands, you have an alt way to source them.
Similar, I wouldn't hate some alt ways to handle some of the religion and treasure fleets in the exploration. While I think you should be heavily penalized to not go for the new world, I wouldn't hate some options for people that don't involve that. Although even there, you have a few sneaky options (Songhai treasure fleets, or Mahajapit relics from their UQ).