“Maybe anyone can do well in Algebra 2 with the proper support. My question is whether learning it is the best use of time for every student.”
Clearly, there are a lot of people who never use advanced math in their careers again after they finish school. This leads to the question of was it necessary? For that individual the answer is no.
The issue is that math gives students a valuable option to change their mind about what they want to do in life. The more math you know, the later in the education process you can go and change to almost any career. When a student stops after, say algebra, they know enough to do a lot of jobs, but there is another segment that quickly closes to them. To have fewer kids toiling away in math classes, we would have to be able to assess what they will want to be when they grow up with more certainty.