Why are NA VCT Open slots being reduced (128 -> 104) instead of expanded?

As far as I'm aware the registration fills up in minutes and there are substantially more teams that want to compete than slots. There are now over 23,000 Immortal accounts eligible to play in a system that has 520 player slots. For reference when VCT Open quals started (Jan 2021) there were just over 10,000 Imm 1+ players and 128 team slots.

Should eligibility requirements be raised? Should an "Open" tournament allow for an expanded field with the growth of Valorant?