Google's slow handling is, whether with this intent or not, working to their benefit and against their customers. Many of us were motivated to update to a Pixel in part because of the substantial reduction in effective cost afforded by the quoted trade-in value, which, so long as the device is in fully functioning condition, meets their prequalification questions, and only showing reasonable cosmetic wear and tear, we should absolutely receive.
On ordering with a trade-In, upon receiving the device, we have 15 days within which to return the new device for a refund. If we send it back within ... let's say 3 days, Google should have it within a total of 5-6 days, and even if it takes them 7 days to provide a quote, we're at 12-13 days. If a revised quote is issued and substantially lower, we're still at a point we can make the decision to accept the reduced quote or cancel and simply return the new device, being effectively made whole to where we were before.
From my conversation with a Google Play Store rep regarding why I still hadn't heard anything on mine yet (not even an acknowledgement of receipt) after 8 calendar days from their receipt as confirmed by tracking:
Note that this is as of yesterday (11/6), by which point they had already had my trade-in received for a full week (as of 10/30).
If this is accurate, there is no scenario wherein we would be able to make a purchase with trade-in under contingency that if the final value offered is substantially diminished we could simple step out of the transaction. It puts the 3rd party in a position where they are less likely to have lower offers declined, as those submitting the trade-ins are now financially committed to the expense of the new device without the recourse of being able to cancel both aspects of the transaction.
Google should take ownership of the fact that this trade-in evaluation period is going grossly beyond the 3 business days quoted at time of trade-in during purchase (or 5 calendar days as indicated in the trade-in packet later received). In the event that a reduced amount is offered, they should extend that window of right to return the new device for refund to afford the purchaser the range of options they would have had had Google and whatever 3rd party is managing the trade-ins honored their stated timeframe.