The biggest threat to DigitalOcean is that AWS, Google, and Microsoft are all going vertical by designing and manufacturing their own chips. Over times they'll be able to get hardware for cheaper, and also more specialized hardware that uses less power. DigitalOcean will have to buy CPUs from Intel or Nvidia/ARM at a higher cost, and eventually maybe even from AWS or Microsoft, essentially giving money to their compe…
I think there's a lot of doubt whether, in the long run, doing your own hardware makes sense for a cloud provider. If you work yourself into a performance dead-end, you can spend billions and end up with a chip that isn't particularly competitive. Whereas if your supplier does that, you can switch suppliers. You could spend $X billion, end up with a chip that isn't particularly competitive and just have to eat those…
Some of them refurbish and operate their own engines (by far the most complex part of the airplane) instead of going to GE or Rolls Royce.
Delta actually operates their own oil refinery.
So airlines are in fact a good analogy.