Once internet connection latencies were above 100ms. ISDN brought it down (for me) to about 30ms, and ADSL got it below 10ms. Now, ADSL2 is becoming more widely deployed, introducing 20ms latency, and more and more homes are being equipped with 3G/wifi gateways, eliminating the copper wire, and bringing latency above 100ms again. I guess it is obvious, that this seriously impacts how to create applications.
Even worse, I have seen 10Gigabit/sec WAN connections with 10-20ms latency, which replace local <1ms ethernet networks when datacenters are consolidated. This seriously impacts the number of network requests your application can do.
This also affects user experience in a negative way - so why is latency increasing? My guess is, that new technologies and increased demand for skilled IT workers make low latency have a cost. The solution is to specify latency requirements, and to put numbers on the costs of high latency.