We were discussing riding the bus to a place that depending on traffic is a 20 minute car ride from SF, or a 2 hour car ride in the worst case scenario traffic.

There are a few bridges that connect SF to other places across large bodies of water, the Bay Bridge and the Golden Gate Bridge. These bridges do not provide a dedicated lane for the buses. These bridges act as a choke point for traffic. As a result, the buses are not reliably on time, because the traffic is hard to predict and it depends on whether or not people have a car accident that evening.

As I mentioned in another comment, these buses do not have bathrooms inside. So you are spending an unpredictable amount of time standing at an unsheltered bus stop, often with no bench to rest on, followed by an unknown amount of time on the bus.

The buses come infrequently enough that if you go find a restroom after waiting a while at the stop, and the bus comes while you are gone, it will be a decent chunk of your life spent waiting for the next bus to come as well.

This might be fine if you're on vacation and you just wanted to explore the Bay Area, but if you live here and work here, this is just too much time!

If you have a car, there is essentially no upside to taking the bus in this situation, which means if you are greedy and choose to drive instead you contribute to traffic by taking up more space on the road.

In contrast, if you choose to take the train, you know exactly how long the trip is going to be, because there's no variable traffic disrupting the schedules. It's predictable. It's convenient. Sometimes the train might get stopped for one reason or another, but the trains come so frequently that this is rarely an issue.

Before your trip, you're also inside a train station, which is sheltered, has seating, and even often has bathrooms.

There's a sign telling you clearly how long until the next train arrives, you don't have to count on something on your phone to find out.

It's pure snobbery

Where I am, buses are heavily subsidised; cost is about $3 per passenger mile. Fares are much cheaper (so cheap nobody ever really thinks about it, other than worrying if they have quarters for exact change).

They are often empty or have 1 or 2 riders.

They are slow, often show up to a stop late, so you have to plan everything an hour early.

They don’t have amenities like bathrooms and are uncomfortable for long trips, even though that’s the only sensible way to use them.

Due to political pressures, they have many, many stops and few express buses, so they are much slower than a car. The stops usually have nobody at them but the driver still has to slow down and check (sometimes they will just skip a stop they know is almost always empty).

The bus depots are not particularly safe or pleasant after dark and have trouble with attracting antisocial people.

Meanwhile, it would be cheaper to just pay for Ubers for anyone who wants them, and just make the Uber show up randomly late to replicate the experience.

There is a market emerging here often branded as “hood Uber”, “Alicia’s Uber” etc of people who will drive you for $1 a mile (cheaper than Uber) negotiated by text message and paid via CashApp etc. It’s completely unregulated. Some are now offering regular service in a minivan on a fixed route taking people to/from employers every day.