Whiteboard interviews are a skill unto themselves, with only a glancing relationship to day-to-day job content, artificially high-pressure, overly performative, etc. You measure hours invested in Leetcode, not suitability for the work.
Take home projects probably collect good signals, but present a high and (crucially) asymmetric burden on the candidate. No one wants to burn a weekend or vacation days pouring effort into something that the employer can just glance at for 5 seconds and throw in the trash. Also, many candidates would prefer to reuse their time investment over arbitrarily many interviews instead of starting from scratch on each company's assessment.
Interviews focused on personality, culture fit, communication skills, and "gut feel" overemphasize the interviewer's personal beliefs. Likable candidates aren't especially likely to be good, and good candidates aren't especially likely to be the kind of people the interviewer wants to have a beer with.