The business model for FirefoxOS didn't make sense, just like the business model for WebOS didn't make sense. Android was cheaper than free to put on phones because Google was willing to share search revenue with carriers. They would not have done that on a FirefoxOS phone before it reached scale, nor would Microsoft, which was pushing its own phones.
I don't buy it. Apple owners pay premium prices for a perception of increased safety and convenience. I feel that way about what WebOS was. There is always market space available for a device people want.
HP played musical CEOs - 3 in less than a year - and one decided they shouldn't be in the phone or PC business. People loved the phones which were objectively years ahead of Android or iOS. It was not a product failure, but one of management.
People loved the phones, but they didn't buy them. The carriers didn't want to sell them because they don't get paid on the backend. As I said, the business model doesn't work.