I felt the same, so I did a bit of digging and you're right. Stories with "Jane Street" in the title or URL, via HN search:

  Year        Submitted   100+ points
  2014-2020   18-33/yr    2-7/yr
  2021        14          0
  2022        25          4
  2023        33          7
  2024        41          1
  2025        61          5
  2026        93          16   

Also notable: 3 of the 16 were this week.

Looks like two things:

1. them publishing a lot more programmer-facing material

2. more news coverage (SEBI ban, Terra suit, ...)

Don't know if it's a deliberate marketing push though, tbh.