How does the Holy Grail come into this? Your characterization of what investment managers do is as much an idealization as you allege mine is. Many investment groups are 5-20 person shops with middle of the road skill sets who are looking to add value to their process. No imputation that by adding predictive services that they will have found the Grail. I'm sure they'd be happy with services that might promise them a 25-50 basis pick-up in return for a product or two.
Or in other words, average people looking to make up for their lack of skill and experience and misguidedly thinking someone else will provide them the answers. Probably the same average people who think a Bloomberg subscription "adds value". You can't polish a turd as they say. Look, I've seen most of the expensive subscription stuff. The vast majority of it isn't worth paying for. There are some that are interesting, but even they aren't 100% consistent. Nothing beats personal skill and experience, and the people with the real experience are not the sort of people selling you commercial "ideas" services like StarMine. Nothing makes up for skill, and if you're someone who's paying for financial advice then you really should be doing your due-diligence and picking and advisor that isn't "middle of the road", because you might as well just go buy an index-tracker or a collective if you're going to be paying for average skill and average performance.