When people keep having "issues" with hotels, the cynicism flag comes up. Perhaps the same is true of corporate management. If they think someone is consistently over-petty or even trying it on, progressively reducing the amount of compensation offered may be seen as a way to discourage the complainant from complaining in future.
I suspect that most of those posting on this board do not generally have a dozen or so issues with a hotel, let alone several hotels. We travel too much and realise that a lot of stuff is just normal. I'd love to have compensation for the appalling design of some hotel bathrooms (Holiday Inn Express, are you listening?), but in the real world that just ain't going to happen.
All of the issues were service issues - I suspect that each issue, if experienced individually, would not likely give rise to most customers, including myself, complaining. But I think if there are a dozen service issues, which the manager of the hotel has not disputed, it seems from your and corporate wage slave's post, that I should be thankful for the 20,000 Hilton Honor points I am getting.
Sometimes, the quality of the room exceeds my expectations, sometimes it does not meet my expectations (as in your example above). That I accept - I would not justify that design of the bathroom issue worth complaining about (provided that the shower/toilet/sink are fully functional).