Dunno about bike infrastructure in San Francisco as I've only been there a few times, but one variable you should mind is that South Lake Tahoe is snowy during a good chunk of the winter. Don't plan to move there and bike around unless you're comfortable biking in the snow.

It can be warm in Tahoe in the summer, but the snow is a certainty and cannot be avoided if you're living there. Tahoe is usually fairly mild, or it has been while I've been there. It's also way high up in elevation, which can cause respiratory problems for some until they acclimate.

SF is all hills, and some terribly steep ones at that, so I don't consider it very bicycle friendly for commuting. Great for exercise, terrible for just jotting over to a friend's house.

As to theft, I don't buy terrible expensive bicycles. When I bike-commuted, I took easily-removable items with me (headlights, repair items underseat pouch, mini pump, water bottle, backpack tied onto a platform on the back). There's a bike lock going through the frame and tire. Someone with sufficient hardware could probably cut through the lock, but they aren't getting much.

I did know some people who bike-commuted in SF, and they just kept their bike in the office -- the company dedicated a conference room to it.

I had an employer who installed a dedicated, card-accessed bike storage area in a lower-density area partway through the time that I was working at one location. I didn't care much one way or the other. If someone stole my bike, which never happened, I'd have just taken a taxi or something and then used my car until I got another bike.

For SF versus somewhere like Lake Tahoe, It's kind of a different situation.

I think that most bike users would prefer to have dedicated bike paths, not just lanes. I certainly would. No matter how nice the lane, on a bike, you're right next to much larger vehicles with little protection.

Also, speaking from a driver's standpoint, there are a lot of bicyclists who do not give a darn about or don't know traffic laws. I see people on the road at night without headlights -- that one boggles me, as I kept a flashing headlight to be noticed and a constantly-on headlight to see and still had a couple of close calls where drivers didn't see me -- biking the wrong direction, disregarding stop lights, and stop signs, not signalling, etc. Having them on the road isn't just dangerous for them, but a headace for drivers.

Plus, bike trails don't create a lot of traffic noise or require a huge amount of space. You can put them where cars won't go.

Somewhere like Tahoe, you can put bike trails more-readily.

San Francisco is urban. Space is at a premium. you can't really go create a bunch of dedicated bike paths unless you're going to raze buildings, build elevated or subterranean bike paths, or disrupt the existing traffic system. Those all have a lot of costs and tradeoffs.

If you look in the South Bay and I believe East Bay, you can find some dedicated bike paths. But because it's lower-density, it's also harder to use a bike for generally getting around. If it works with your commute -- the Googleplex, for example, has a major bike trail going through it -- then bike-commuting might be a good option. But I think that just generally getting around on a bike would be more-annoying.

Last I heard, SF was creating a "grand central" mass transit station, which apparently opened last year, which would finally link CalTrain, VTA (the SF light rail system) and the SF bus system. Apparently, BART (the wide diameter rail to the East Bay) wasn't going to be part of that. I dunno what automobile and bike parking at said central station is like, though I hope it's well-provisioned. But that -- though it's not bike infrastructure per se -- might make bike use more-amenable for many, just by making multi-modal travel in the city more practical.

My own take is that biking is a nice way to stay in shape, but I'd be unwilling to rely only on a bike for transport. SF or NYC are probably the only two places in the US where I think that it's reasonable to possibly do that, and I still wouldn't want to. I don't want to bike when it's raining.

If you're like me, that affects what bike infrastructure is reasonable. I want access to recreation trails and a relatively-low-auto-traffic -- ideally none -- bike commute route, since that's overwhelmingly the route I'd typically use the most. Bike access on mass transit is nice to have, but I don't care all that much unless I need it for a commute.

I'm fine with not having bike access to some random restaurant or store.

But for someone who wants to go bike-only, the requirements on bike infrastructure are very different.

And for someone who doesn't want to bike-commute, just have recreational trail access, what good "bike infrastructure" is may look very different again.