And you don't even need to be in shape anymore with e-bikes...
Edit: An idea that came to mind, someone run with this. Bike lockers would be an amazing feature that likely could curb a lot of the issues. Something with a secure lock built in (like biometric or complex pin), 360degree cameras, and an insurance policy. I'd have paid hourly for that service if I still lived in the city.
There's also Revel scooters if you need more power and space for groceries, Lime scooters if you like getting injured, and there are plenty of tiny electric vehicles now that you can buy, wouldn't call a bicycle but can easily be brought into grocery stores etc. They're all over SF. I don't think it's exactly out of place to call out alternatives when discussing whether biking is a viable commuting option.
But of course those spots also mean avoiding poops, drug deals, a homeless person in the 1% group that assaults people, and other general shadiness. Generally fine for a huge man, much worse for a dainty woman.
Edit: and I'm a 0 transfer kind of person. Albeit I tolerated switching from Muni to Bart in same station on market street. And because my own personal tolerance for walking was higher than average, I'd often just look for the route that allowed me to ride one ride even if I had to walk 60 minutes across the round trip.