Bufferbloat is potentially almost unlimited, assuming that the people who built it are idiots (a safe assumption for most consumer gear) it basically just depends how much they were willing to spend on RAM.
For example, let's say we can move 10Mbps, and we've decided to use 10 megabytes of buffers to make our new WiFi router super-duper fast. Do a big download, the buffer fills with ten megabytes of data, that's eight whole seconds of transmission, now the latency of packets is eight seconds, so that's 8000 times larger than your "I assume less then 1ms".
Back around 2006, I had a RAZR that I figured out how to use to tether my computer onto Verizon’s 1xRTT service. I’m not sure which part of the system was to blame, but something had massive buffers and a strong aversion to dropping packets. If the connection got saturated I could easily see ping times of two minutes or more.
Why would a single big download fill the buffers? Router → LAN is typically an order of magnitude more bandwidth than internet → router, so shouldn't the buffer be emptied faster than filled?
The bottleneck is at your ISP's CMTS or DSLAM and your modem. e.g. The DSLAM has 1 Gbps in and only 40 Mbps down the line to your VDSL modem. Or your cable modem has access to 600 Mbps of capacity but your plan is only 100 Mbps so the modem limits. So there's quick stepdown: 1 Gbps, 600 Mbps, 100 Mbps.
For downloads it's buffers in your ISP's hardware that matter. For uploads it's your router's egress buffer.
e.g. You are syncing gigabytes to Dropbox. A poorly designed router will continue to accept packets far past upstream capacity. Now that's there's 2000 ms of bulk traffic in the router's queue, any real time traffic has to wait a minimum of 2 seconds before getting out.
Depends on the router, and the load. If you have a 100mbit uplink and 4x1 gig on the downlink side, you could easily have 10mbit of packets arrive in 3ms (70 packets per millisecond), but would take 30ms to send those packets. You can either
1) Drop -- despite total trafic being only 10mbit a second
2) Queue -- introducing a delay of 30ms.
In reality you'd put latency critical applications (voip etc) at the top of the queue so the pcakets get transmitted without the delay, and your facebook packets get delayed by 31ms rather than 30ms.
As much as 2000 ms when saturating the downlink with a long file transfer. Web browsing stops working and nothing loads in as every little resource request takes two seconds.
For example, let's say we can move 10Mbps, and we've decided to use 10 megabytes of buffers to make our new WiFi router super-duper fast. Do a big download, the buffer fills with ten megabytes of data, that's eight whole seconds of transmission, now the latency of packets is eight seconds, so that's 8000 times larger than your "I assume less then 1ms".
{Edited to correct numbers}