Why so many institutions choose their own systems for application rather than universal systems like mathjobs.org or interfolio where letter writters don't have to upload their letters multiple times?

Custimized questions don't seems to be the reason since mathjobs.org and interfolio also offer the same option (or at least let the applicants address this in the separate pdf uploaded)

Cost? I don't know how much mathjobs.org or interfolio charge each institute to use their system, but it seems that it is also not easy or free to build and maintain their own application system.

So there should be reasons other than these. Why can't every institute use mathjobs.org or interfolio, making the lives of letter writes easier?

Why do so many institutions choose their own systems for application rather than universal systems like mathjobs.org or interfolio where letter writers don't have to upload their letters multiple times?

Customized questions don't seems to be the reason since mathjobs.org and interfolio also offer the same option (or at least let the applicants address this in the separate PDF document uploaded)

Cost? I don't know how much mathjobs.org or interfolio charge each institute to use their system, but it seems that it is also not easy or free to build and maintain their own application system.

So there should be reasons other than these. Why can't every institute use mathjobs.org or interfolio, making the lives of letter writes easier?

Why so many institutions choose their own systems for application rather than universal systems like mathjobs.org or interfolio where letter writters don't have to upload their letters multiple times?

Custimized questions don't seems to be the reason since mathjobs.org and interfolio also offer the same option (or at least let the applicants address this in the separate pdf uploaded)

Cost? I don't know how much mathjobs.org or interfolio charge each institute to use their system, but it seems that it is also not easy or free to build and maintain their own application system.

So there should be reasons other than these. Why can't every institute use mathjobs.org or interfolio, making the life of letter writes easier?

Why so many institutions choose their own systems for application rather than universal systems like mathjobs.org or interfolio where letter writters don't have to upload their letters multiple times?

Custimized questions don't seems to be the reason since mathjobs.org and interfolio also offer the same option (or at least let the applicants address this in the separate pdf uploaded)

Cost? I don't know how much mathjobs.org or interfolio charge each institute to use their system, but it seems that it is also not easy or free to build and maintain their own application system.

So there should be reasons other than these. Why can't every institute use mathjobs.org or interfolio, making the lives of letter writes easier?

Why so many institutions choose their own systems for application rather than universal systems like mathjobs.org or interfolio where letter writters don't have to upload their letters multiple times?

Custimized questions don't seems to be the reason since mathjobs.org and interfolio also offer the same option (or at least let the applicants address this in the separate pdf uploaded)

Cost? I don't know how much mathjobs.org or interfolio charge each institute to use their system, but it seems that it is also not easy or free to build and maintain their own application system.

So why can't every institute use mathjobs.org or interfolio?

Why so many institutions choose their own systems for application rather than universal systems like mathjobs.org or interfolio where letter writters don't have to upload their letters multiple times?

Custimized questions don't seems to be the reason since mathjobs.org and interfolio also offer the same option (or at least let the applicants address this in the separate pdf uploaded)

Cost? I don't know how much mathjobs.org or interfolio charge each institute to use their system, but it seems that it is also not easy or free to build and maintain their own application system.

So there should be reasons other than these. Why can't every institute use mathjobs.org or interfolio, making the life of letter writes easier?