This is actually the most surprising thing I've seen since we started Triplebyte. Originally I'd assumed that every company complaining about how difficult it is to hire engineers, would be moving every candidate through their process as quickly as possible. In practice we learnt to stop working with companies who were too dysfunctional to get back to candidates promptly - even if it's just to let them know they needed a few more days to make a decision.
We'll also often see dysfunctional companies switch to the extreme opposite end of the responsiveness spectrum once they've made an offer and start pushing candidates to make a decision immediately. Better to have been responsiveness throughout the process. I suspect companies still underestimate how much that makes a candidate more positively inclined towards them once they're at the decision making stage.