You have every right to your opinion but Bushmaster has been making the AR style rifle longer than any other manufacturer except for Colt. I would hardly call that an "oddball brand". They have been in business since 1976 and are still doing quite well selling what you call a hobbiest grade rifle. Strange that so many PD's would depend on a hobbiest grade weapon.
The new Bushmaster is not the same company as the one you're referring to. Bushmaster was bought out and their manufacturing facility was sold and most of their employees were laid off. One of the laid-off former heads of Bushmaster bought back his old facility, hired back most of his old employees, and started Windham Weaponry.
So the new Bushmaster is a new company making a different product, and Windham Weaponry is basically the same thing as the old Bushmaster.