I didn't say there was hostility towards one tech stack or another, I was just stating my observations/experience. In my experience, once a firm has one or two tech stacks, they don't really want to deviate too far from what's entrenched because, well, they need to have the talent on hand to support everything. This becomes exponentially harder if every developer chooses their language/framework of choice. Generally, though, if there's a compelling reason to break from the core competencies of the firm, exceptions may be granted (this was how Python first got its foothold in my first firm - I could easily, e.g. generate, Python wrappers over my C++ APIs that allowed me to do everything my business users wanted while still maintaining compliance control and audits over data changes).
Typically, you can usually tell the age of the trading firm by the tech stack. Older companies are usually on C++ and have millions upon millions of existing legacy code that works, so there's little impetus to rewrite in the latest shiny. Younger firms are more likely to have embraced Java and younger yet, C#. This doesn't always hold true, though, it's just a generalization of my experience.
In my 15 years in finance, I spent 9 years at my first firm, and when I joined it was purely C++, with some perl to move data around between vendors and systems. There had been some Java, but we had a bad interaction with Sun Microsystems (at the time) and our CEO came down hard and kicked Java to the curb (and we migrated off of Sun/Solaris onto Intel x86 & Linx & C++). Towards the last several years I was at that shop, C#/WPF had been embraced for all new UI work, and even some rewrites of existing MFC apps were in progress. Python had also largely replaced Perl for all new scripting/data munging and had also been embraced by the quants. All of the servers still ran on Linux and were in C++ when I left ~6 years ago. There was even talk of migrating from Sybase on Linux to MS SQL Server. That didn't happen in my time, but from former colleagues I've kept in touch with, they've pushed forward on that. I don't know if they're using SQL Server on Windows or on Linux, now that that's an option.
My current shop is the oldest shop I've ever worked for (founded in the 70s) and is entirely a Windows/C# shop. They brought me on this year to help with their build out of Python at the firm (mostly for our quants). I'm actually really enjoying this position, because they're new to Python, but I've got +15 years experience with it, there's a lot of greenfield development and next to no existing legacy code, so I largely get to drive style and architecture.
Typically, you can usually tell the age of the trading firm by the tech stack. Older companies are usually on C++ and have millions upon millions of existing legacy code that works, so there's little impetus to rewrite in the latest shiny. Younger firms are more likely to have embraced Java and younger yet, C#. This doesn't always hold true, though, it's just a generalization of my experience.
In my 15 years in finance, I spent 9 years at my first firm, and when I joined it was purely C++, with some perl to move data around between vendors and systems. There had been some Java, but we had a bad interaction with Sun Microsystems (at the time) and our CEO came down hard and kicked Java to the curb (and we migrated off of Sun/Solaris onto Intel x86 & Linx & C++). Towards the last several years I was at that shop, C#/WPF had been embraced for all new UI work, and even some rewrites of existing MFC apps were in progress. Python had also largely replaced Perl for all new scripting/data munging and had also been embraced by the quants. All of the servers still ran on Linux and were in C++ when I left ~6 years ago. There was even talk of migrating from Sybase on Linux to MS SQL Server. That didn't happen in my time, but from former colleagues I've kept in touch with, they've pushed forward on that. I don't know if they're using SQL Server on Windows or on Linux, now that that's an option.
My current shop is the oldest shop I've ever worked for (founded in the 70s) and is entirely a Windows/C# shop. They brought me on this year to help with their build out of Python at the firm (mostly for our quants). I'm actually really enjoying this position, because they're new to Python, but I've got +15 years experience with it, there's a lot of greenfield development and next to no existing legacy code, so I largely get to drive style and architecture.