It's just important to know how the theory has been developed over time, and stress how even the development of dialectics is dialectical itself! Everything is a process.

Marx didn't develop dialectics in a vacuum, it was developed by building up from Hegel's dialectics, which in turn were built from someones else. And surely, people will continue to develop dialectics by building up from Marx. It's all a process.

We have to respect the previous philosophers for being part of the process but we must not idolize them, even Marx. Even if Marxism (dialectical materialism) may seem as the end of philosophy, there will come a time were someone builds up from it and renders it obsolete. It hasn't happened but it will.