I am not a miner but overall, the financial economy is co-related and works dependently, and grows equally in parallel time. So if, the salaries are increasing that's because if you are buying an apple for let's say $5 for 1KG that will be $10 for 1kg in the near future. The same goes with BTC, as when the reward is reduced to 3.125 (almost half) the price will be doubled and i think miners will be able to make the same reward or maybe more, just my thoughts, as the transactions fee will be increased too, so they will earn from validation too.

As prices will definitely go up due to high demand and low supply, this will increase the BTC prices and miners will be able to make the same reward or maybe more there is definitely a possibility of less profit if the price didn't increase. Plus the image you have used is really amazing I would love to see a resource of it.