enough to know who comes off worse.
which is more replaceable
A: lightbulb ALT
B: trained teacher
I'll give you a hint, the answer doesn't start with B.
Actually I think you are missing something here........in reality B.
You want to know why? Just about any local education office has a list of fully qualified teachers at it's finger tips and in any worst case scenario for a school, a teacher figuratively speaking drops dead, the education office can and does supply a substitute teacher within hours or a few days.
The impression for many is that ALT's can be replaced quicker or easier because just about anyone can do the job. And while not totally a fallacy here is due to the actions of prior ALT's themselves. Too many ALT's got complacent in their jobs and got lazy as well, and the schools didnt like carrying dead weight. Systems got put into place to move people out after 3 to 5 years and just about everyone got accustomed to that including teachers, ALT's, BOE's etc etc. everyone.
So the problem widened further because of the economy, language schools, increase in awareness of Japan, and more and more "natives" found found their way to Japan to find work, many if not most on a temporary basis, and within these people as well came many over qualified teachers too.
The problems increased exponentially, anyway I digress.....
Point is that the system wasnt and is still not in many ways prepared to handle ALT's that take their job seriously and want to either make a life of it or make an effective change in the way students look at English.
Now then replacing the ALT depends upon totally the location of the school and what system the BOE or ed office has in place for hiring and firing of ALT's. Let's keep in mind that not all ALT's are native English speakers as well. There are Japanese ALT's too. Anyway it is not always easy to find someone as it seems, many places that I know about dont just take someone off the street and give them a job. Although that happens I am sure and that helps to perpetuate the problem or impression that anyone can do the job because they dont have to have the Japanese teachers license to work in the school.
Depends on the location.