"The internet and technology in general have done some great things for music but making money is harder than ever."I don't think we can conclude that at all, especially in this case.
In the pre-Internet era, the niche for modernist cello music would have been an incredibly small set. If she were supremely lucky, she'd make it to Carnegie Hall every few years, and maybe sell a couple hundred CDs at a given performance there. Her radio airplay would have been limited to NPR, and perhaps a smattering of tiny classical stations. She'd have been touring pretty much 24/7, mostly to small venues, and basically hustling albums out of the back of her van.
The internet has expanded niches, blurred genre lines, eased access, increased distribution, and basically enlarged the footprint that someone like Zoe Keating can make on the world. She might be getting a smaller slice of the pie, but her pie is undoubtedly much, much bigger than it would have been 20 or 30 years ago.
If anyone opened this spreadsheet expecting to see a glamorous story about how Zoe made $3 million in 2 days, I would suggest they reexamine their expectations for the size of the experimental cello music market. She's doing respectably well, given her niche. I would also assume she has supplemental income streams from concert appearances, which have historically been the bread and butter of classical musicians. (Which is not a lot of bread and butter, to be clear, but it pays the bills).
A more interesting discussion, IMO, would be a breakdown of how Spotify, iTunes, et al. have had disparate impacts on different types, flavors, and "sizes" of musicians. For instance, how has the Internet treated the Zoe Keatings of the world, vs. the Beyonces of the world, vs. the Bjorks of the world, vs. the Lil' Waynes of the world, and so forth.