Agreed. I've spent a ridiculous portion of the last 4 years in taxis and liveries in the NYC metro area and a few other major cities in the US and several in western Europe. Speeding has been an absolute constant; no exceptions whatsoever. Is there actually a place where taxis do not default to pushing speeds to the highest extent possible?

Here in Amsterdam taxis speed all the time, to the extent that they are the most dangerous cars to keep an eye on while biking.

This might be due to the economical aspect of a taxi ride. The base fee starts at 7.00 euros sometimes, just for walking into the taxi. I don't have the exact fares data, but although they are earning additional money during the whole ride, for short rides it's clearly more remunerative for them to get to destination as soon as possible to be able to take another one.

In Abu Dhabi there is fleet of taxis which are "GPS controlled". The driver stayed exactly at the speed limit on an empty 4 lane highway at night for half an hour. Somebody in their operating center probably has a job to watch the drivers.

Or they might log the speed every n seconds and store it in a file for a program to analyse later.

This is the more typical use case. Managers/safety officers will want a report of "who sped the most in the last X days" both in terms of highest speed and average over-the-limit driving. In extreme circumstances, such as when onboard sensors detect an impact or impending rollover, the logging can ramp up to multiple times per second. Great for insurance purposes.

Beijing taxis most often don't speed, but that has more to do with the traffic and speed cameras than anything else. I've seen cars implode at night on the ring road going 2x the limit, it is quite an experience to watch their wheels just pop off.