> The main problem is that, if they wanted to, it shouldn't take Apple/Microsoft/Google/Amazon too much work to put out a comparable product and offer it for free.

Apple[1], Microsoft[2], Google[3], and Amazon[4] already do have comparable products, with comparable prices[5].

1. https://www.apple.com/icloud/icloud-drive/

2. https://onedrive.live.com/about/en-us/

3. https://www.google.com/drive/

4. https://www.amazon.com/clouddrive/home

5. https://www.cnet.com/how-to/onedrive-dropbox-google-drive-an...