Why doesn’t ship energy count towards our personal daily raid tickets count?

Mainly because you get 540 free energy between normal amd cantina energy every day. Counting ships energy towards your 600 would see everyone getting their 600 without a need to refresh.

If they were to count ship energy they would do it by increasing 600 to roughly 800 and increasing the cost to launch all raids by a third to maintain the balance where you have to spend crystals on a refresh in order to max out ticket generation and have raids launched as much as at present.