F500/government are conservative and tend to stick with the vendors they know, which is why Azure has gained so much traction despite being worse than AWS & GCP pretty much across the board.
Trust in handling data doesn't really come into this; if anything Google has a very strong reputation for security.
> ie trying to not do new things because it takes more work to change
That's not what the word conservative means, not by the dictionary or even politically.
Conservative is the averse to change or to hold traditional values without logic. It's more like a type of fear. Even if the change was easy or have 0 cost, a conservative entity won't do it.
Trust in handling data doesn't really come into this; if anything Google has a very strong reputation for security.