What will happen if Tech Giants Like Google, Microsoft, Amazon starts investing in Bitcoin or Altcoin Mining?
If they did it right (developing new generations of ASIC's and running them in places with low energy costs), the diff would probably rise even more than it already did, forcing some smaller miners and miners with relatively high energy rates to stop mining.
For the rest, not much would probably happen, unless they suddenly added a ton of hashrate to the network one week, and took everything offline a couple months later... In this case the average time between two blocks would first be smaller than 10 minutes untill the next readjustment, then when they took their farm offline it increase drastically untill the next readjustment (every 2016 blocks)
It will be very, very difficult to keep developing ASICs that are better than past generation by the magnitude of order we have been seeing in the past few years. This video by Andreas A is very useful in understanding this fact.
What I don't get is, it will always be way cheaper to do it in china than in the rest of the world due electricity low prices... so how can we end china's monopoly in hashing power while this continues being the case?