> I speculate that previous administrations have been just as corrupt, but much better at hiding it.
This is just the perennial "both sides" argument and I don't buy it. The excuse is that "everybody does it and so we need to cheat to keep up at all" and although I'm sure president Trump believes it's true, it's just another example of the distorted reality of the current administration.
There is major republican control over all three branches of government and the president isn't actually inept, but look at how hard it is for him to get away with blatant corruption. The fact of the matter is that (at least for now) there are apolitical people in government who are willing to stand up to abuse of power and they typically do so. There's enough of them that I don't believe in some conspiracy that "all politicians have been committing crimes and everybody know it". That's just a political argument with no grounding.
tl;dr The number of abuses of power from the current administration isn't because they're worse at hiding it. It's because the president cheats more and has been doing it his entire life even before the presidency.