This is the reason why.
Washington introduced the gold pants after months of hints from Bruce Allen, the new GM/ son of a longtime Redskins head coach, in 2010 during Donovan McNabb's ill-fated stint in Washington. The fans loved them, and their use slowly increased over the 2010 and 2011 seasons while Washington floundered in mediocrity. The first use of the gold pants with white jerseys came late in 2010 if I remember correctly, and by 2011 it was more common than not to see them on the road.
In 2012, RGIII and the Nike contract happened. Washington stopped wearing the burgundy pants at this point. At home, it was either burgundy/gold or burgundy/white (typically during 1PM home games) and white/gold on the road. The Redskins were really good at this point, and nobody was really talking about the uniforms.
Through 2013-2015 the Redskins returned to relative mediocrity but began to improve, move past the RGIII disasters, etc. And it's my understanding that the fans began to realize the gold pants had completely taken over and it stopped being "the fun new thing" and became "the same old thing." Went from being the "new option" to being the "restricting option."
So it started with some blog posts about the burgundy pants, and then they surprised everyone and brought them back for the start of 2016. And it seems we finally have what most people want. A healthy amount of gold pants, with the classic Washington look still in the mix (I would argue a top-five NFL uniform from the point of historical significance).
Now my perspective on this is admittedly a bit more invested than the average fan, who probably had a couple random thoughts about the Redskins uniforms over this period instead of literally knocking on the window of Bruce Allen's skybox during a Week 2 game during high school and holding up a sign that said "Where have the burgundy pants gone?" only to get a laugh and have him turn his head, angering me for months on end, going so far as to bring it up at some stupid season-ticket holder even later in the year when I inadvertently found out about the new throwback uniforms and was lied to about some rule about only being allowed three pairs of pants per team... sorry.