CCP has been slowly (because detangling undocumented code is a PITA) separating out systems within the EVE engine so that they operate as independent entities instead of a single mass structure. However, they aren’t 100%-all-hands-on-deck on this effort, because they also have to release new content, QoL changes, and balance patches, too. So, we see slow but steady improvements in underlying systems as functionality is separated out and migrated to the newer codebase that not only documented far more robustly, but also doesn’t lump unrelated functionality together (making it much easier to maintain going forward).
All of this is still limited by absolute hardware constraints on simultaneously activities - which underpin the majority of flight and combat activities. So even making all of these improvements won’t make a massive noticeable difference to server population limitations in combat, simply because that’s not a code restriction. CCP is already on the cutting edge for simultaneous activity, so there are distinct limits on degrees of improvement - as hardware improves, so do the server limitations in these situations.