Those are good points, however, that section of 110 needs to have the capacity greatly increased.
Increasing the capacity of almost any freeway in L.A. is a lost cause at this point. It would be smarter to invest in ways of getting more cars off the roads during commute hours. Leave the freeways to the thousands of extra trucks and delivery vehicles that our online shopping obsession has created a need for.
I can see both sides to it, but frankly, Los Angeles is a car dominant city as most American Cities are anyways, and investing in rail seems to be more of a lost cause to me than widening freeways more due to the way development is in SoCal. Mass transit is good for cities like NYC but for a city as spread out as Los Angeles, cars are fine. I think if they would take the route Dallas has and offered more tolled options and less capital due up front with the companies financing the projects, they could create a variable elevated tolled network with adding 3 tolled lanes each way, an additional general purpose lane each way, and additional HOV lane each way, combined with bridging the freeway gaps, offering new truck routes like what they plan on doing with the 710, fixing the interchange deficiencies, and expanding the subways or any other grade separated rail where applicable, Los Angeles's traffic problems could be solved. It would require billions, but that is up to the people of SoCal to decide if they want to fix it or not. Simply expanding mass transit isn't going to do anything.
I love MagLev, but the operating costs would likely be too high for the density, so intercity HSR between San Fran, Vegas, SD, Ventura, and San Bernardino would also help with commuting. Freeways such as the 405 could be widened to 8 general purpose lanes each way and would with 2 HOV lanes each way and 6 tolled lanes each way, I promise you that the traffic issues would become no existent on that highway.
Simply put, it doesn't have to be one or the other. But spending 120 billion in a mega region over 50 years is nothing. I don't know what else can be done. Something very ambitious, but the issue can be solved. I think it's just a collaboration on all parts.