Earlier quoted context omitted.
Rewriting it in Rust isn't automatically faster and more importantly Eve's gameplay is constantly being iterated on and Rust has proven to be bad for that. Moreover, most of Eve's bottleneck isn't single server speed, it's mostly network IO and database queries and latency. The big TiDi skirnishes in particular are slow due to this.
On the iteration: I'm not sure that's the case anymore? Sure new content is added but it's largely within existing systems. The game is closing in on 25 years old at this point. I've no insight into what specifically their bottleneck is. The database doesn't sound like it'd be a factor, though, since the slowdowns are isolated to single nodes handling the area with players and don't effect others.
It doesn't sound like it because you haven't been paying attention. By and large, the TiDi slowdowns are because of network IO (i.e. too many players connected to a single node), but the database causes stutters when large numbers of ships are exploded at once.
DB needs to update inventory, skills, implants, and killboards which requires multiple round trips. Moreover, while these round trips to the DB happen, the core processing threads often end up yielding waiting for the SQL Server instance to respond.
But again, I only mentioned it as part of the problem. The core of the issue is definitely Network IO. Someone activates a module or weapon, you need to send that info to 1-10k players as a packet update. That's the source of delays, not processing speed. Rust won't magically speed that up, the network layer is already written in C.