BUR is not really competition for LAX (just under 6 MAP-million annual air passengers in 2019 for BUR versus 88 MAP in 2019 at LAX), providing a limited schedule of mostly regional (top six arrivals and departure numbers are from other CA cities-OAK, SAC, and PHX and Las Vegas) with domestic only services.

BUR is jointly owned and operated by an authority made up of the cities of Pasadena, Glendale, and Burbank, and it doesn't "throw off" much if any "cash" to Burbank that I've seen.

Those "in the know" who use the Metrolink connection to and from BUR from downtown LA are a miniscule number of plane passengers at BUR, with actual counts I've personally reviewed that are "per day" in the range of up to several dozen on and offs from the trains, on a good day....

LAX has (or had prior to Covid?) more air travelers and employees coming from the current "bus feeder" connections to the Green line (even into the "hundreds" on a good day), than BUR has getting on or off from Metrolink. With the opening (?????) some day, of the new Crenshaw line Century station, and completion of the people mover, I expect both more air travelers, but mostly more employees, will be able to use rail to access LAX.