[user5994461]

That's not the case in JP Morgan. Development is very centralized.

There are like 3 to 6 major platforms used inside of JP Morgan, depending how you count (the oldest one is deprecated and being migrated away which will never complete, while the newest one is nowhere near working and will not have anything running for a long time).

The largest one regroups maybe 30% of all the developers and developments in the firm.

The Perl system was underlying on of these platforms, and has clients for use in all other platforms, so it was quite ingrained across the entire company really.