Using a perfect toolchain for modeling every aspect of a system is possibly a dream. But perhaps one of you can recommend a tool, that supports most systems engineering tasks.
Systems Engineering is a broad term, but for practically anything that I've seen in the engineering world can be accomplished with MATLAB and Simulink coupled together. There are free alternatives, but not usually as well supported or mature.
There are also a load of specialised toolboxes and add-ins for the MATLAB environment that I'd be really surprised if you couldn't find something for whatever domain you are working in. I've never really needed anything else aside from Visual Studio to compile code for performance-critical or application layer things that need to extend capabilities or work with hardware closely.
Thank you for your answer. So I assume you speak about software-systems. I thought about more complex Systems integrating more than just one engineering domain. So MATLAB is still a tool that works even in that area but tools like IBM Rhapsody or Enterprise Architect are perhaps more used.
My experience is more in design and engineering for physical systems, but I have also spent time in Human Factors where there weren't really standardised tools and we essentially built what we needed. I imagine things like Rhapsody are more for everything outside of that remit, like lifecycle management, planning and training systems. In that case I would probably look at the enterprise software providers (like IBM of course) and see what they can do for BI (Business intelligence) as it's likely there is a lot of overlap with the analytics / vendors that do SysEng and BI work.