Amy Gebler says she’s “obsessed” with scoring delivery time slots for groceries, which have become a rarity as demand for doorstep drop-offs soars during the coronavirus crisis. “I have carts on three different platforms and I’m constantly refreshing,” said the 48-year-old single mom based in Seattle, one of the country’s first coronavirus hot spots.

During the day, the delivery websites for Amazon Fresh, Safeway and QFC, the local Kroger-owned chain, are a constant fixture on her laptop as she works. In the middle of the…