You were late, you set the time to leave. If you didn't allow for a few extra minutes(most likely no longer than 5-10 mins) it's on you that you were late.
Take responsibility for your own actions and quit looking to mommy MV to clean up after your decisions didn't work out.
This post DRIPS with entitlement. "I was late so it was the fault of someone else"
Good grief.

OK, so perhaps I am a big baby who whined a bit when I got back. I was upset and it was nothing to do with leaving late.

However, how long should finding a parking spot take? I had given myself 20 minutes for a 15 minute drive and 10 minutes to find parking, in other words left 30 minutes which should have been plenty. Fortunately (or perhaps not so depending on which way you look at it), those I had to meet were also late for exactly the same reasons.

What is an acceptable length of time to park? Should 15 minutes of driving through lots and garages be the expectation for any visitor? In Silicon Valley, home of innovation and high tech gadgetry, shouldn't a few high tech gadgets and apps make the lives of ordinary people being able to park be the way of life rather than hunt or stalk? In the end, I stalked some pedestrians to find their parking spot, should this be the way the to do it?

Castro is a destination lunch time meeting place. You have excellent lunch time vibes in your excellent lunch time restaurants. The restaurants themselves do a great job in getting the people in, being served and able to get on their way in a timely manner. What you don't have is an efficient parking situation. Evening parking is the same, the after work and happy hour crowd are in the same situation.

For my next meeting in a restaurant, I am seriously planning to find a restaurant near to the highway with better parking. It is no longer about the food, but the parking which is the more important criteria.

Your downtown restaurants are going to suffer if you can't support them with better parking strategies.

Seriously, you could have parked 1/2 a mile away and walked to the place in 10 minutes if it was that urgent. SOLUTION!
I've been coming to DT MV for the past 30 years for lunch, and it was way worse more crowded during the .com boom days. I wonder how people survived as we didn't even have smart phones?!?! haha.

Yes, it would be nice to have some gadgets, but the lack of them does not mean I'm doomed to be late and inconvenienced. C'mon, be real! YOU yourself are the solution, use that resource!
Maybe nobody will come to MV for lunch because all the parking lots are full of cars...belonging to people who have come to MV for lunch.
That's like saying the restaurant that is always crowded will fail because nobody can get in. Look inward for solutions, not outward.

Of course, until the local residents demand RPPs, as in Palo Alto.

It is clearly a matter of "proper preparation preventing pi$$poor performance" in the matter of the original poster being late for an appointment.

That said, it would be nice if there were signs on our parking structures that could let one know if the lot is full or not. I've seen similar systems elsewhere. Anyone know if they are absurdly priced or not?

Dear PA Resident:

You need not apologize for a really good, helpful idea to aid everyone's efficiency in parking. Provided the electronic display of amount of available parking in a structure is accurately & instantaneously updated, it will help keep business coming to MV, will save gas for everyone searching for parking, as well as saving everyone time & frustration. Thank you for this smart solution to yet more and more snafu creation in the Bay Area due to the big money made from jamming more and evermore people into what used to be well balanced communities. Our species doesn't really have to keep multiplying until we crowd ourselves and every other species off the planet. And we certainly don't need to import people to live here. Google and the other big ones should hire locally instead of altering this prime location to suit the very well off at the expense of people of all income levels.