What you experienced is one reason I have a hard time making the multi-day, multi-pier trips that I used to make. During the summer months, or on weekends the rest of the year, almost every pier in the southland sees large crowds and often parking lots that are filled to the brim. Hitting 3-4 piers a day is hard simply because of the time involved in driving and parking. Of course there is also the cost which, depending upon the piers, can sometimes run you $50 a day and the motels that generally run $75 and up even for a budget motel. The will is still there but the way is much more complicated.
I noticed this exact same issue the last couple of years. If I'm not to the beach/park/pier I'm visiting by 8:00 am at the latest then it's
best to just turn around and go home. Doheny, which doesn't have the greatest variety of fishing, and San Onofre, which has about a 3/4 mile walk
and a hike down a steep trail to get over the bluff, are the beaches that usually have parking when all others are packed full. Doheny has awesome
picnic areas and the harbor fishing pier is there, but the harbor pier is definitely in the "don't bother after 8 AM" parking situation. The jetties are
pretty much the same situation.
The cost of pier-parking is one of the main reasons that I buy the $195 state park pass and almost exclusively surf-fish the shoreline... Fortunately, if I'm willing to put in the 90 minute drive most of the time, I can make day trips out of it rather than needing a hotel if I hit most OC or LA beaches... I hit
OC more than LA though just because of the parking situation (ie more state parks where I can use my pass). I wish I could find $75 hotels for the occasional overnight trip, but I haven't seen those rates during the summer or on weekends in years. I get campsites when I can (Once again Doheny,
San Clemente, San Onofre, Crystal Cove, never been able to get Bolsa Chica) in OC, and they still run $45/night. Lots of campsites in San Diego area
as well. If you have a camper van or if you enjoy tenting it, it's a cheaper way to stay, and if you have a partner along to split the cost it's even more
economical. I very highly recommend the Sycamore Canyon campground in Ventura near Point Mugu. It's absolutely beautiful with some of the
weirdly grown trees...