Are variable prefixes ( Hungarian ) really necessary anymore?

NO!

In fact, Microsoft’s own style guidelines (where the practice originated) now recommend against it. In particular, see the section on General Naming Conventions, which includes the following text (in bold type, no less):

Do not use Hungarian notation.

Of course, these guidelines are not binding or mandatory outside of Microsoft. However, this is the published recommendation of the platform vendor, and it goes beyond merely removing the positive recommendation from any prior guide, to instead a strongly-worded and emphasized negative recommendation today.

In other words, don’t use them anymore.