It's a bigger pain-in-the-ass to run a property as an STR compared to renting to some local on a yearly lease, since tenant turnover always requires a variety of owner/prop-manager/property interactions (cleaning, fixing stuff, finding the right seasonal listing price, interacting with people unfamiliar with the area, and a big issue of dealing with 'vacationer' collateral damage: trashed apartment, pissed-off neighbors, etc.).
That final hurdle (the 'pain-in-the-ass bottleneck') is almost completely mitigated in the current manifestation of Airbnb. We are at a tipping point where corporations buy dozens, hundreds, of residential properties and automate the entire STR process. Vacationers book online, they show up at the STR and punch-in a pin code to open the front door (no need to shake anyone's hand), vacationers stay for a few days, leave the STR in whatever state of affairs, later that day some contracted cleaning staff shows up and cleans the mess, washes the sheets etc, and resets the door-lock on the way out. Voilà, fully automated STR. Rinse, repeat. And the more STRs the corporation owns in a city, the lower the overhead cost per unit.
If you take a look at the map of their San Diego offerings, you'll see a bunch of pins on the map with numbers like <9>, <12>, <14>, up to <27> it seems. But if you look closely, that doesn't mean they own 27 total apartments in San Diego, that number means they own 27 apartments/lofts under that single pin. Sonder is a Silicon Valley based company, waddayaknow.
