I never thought of that, good idea. Obviously they didn’t make it because it would make the show obsolete to have the ability for an information gathering device to be literally everywhere at the same time, allowing real time data collection of everything imaginable.

But the question stands, why wouldn’t starfleet build them after the discovery on voyager? Possibly the most enormous tactical development in the history of the setting, starfleet could literally observe what happens in the romulan government from their headquarters, or monitor the Borg up close without any risk.