The only reason Texaco GAS stations are going away is because of the merger. The merger would have caused a monopoly in mnay markets in the west with a Texaco on one corner, the Chevron on the other. To minimize that, ChevronTexaco was forced to give up the rights to the Texaco Brand gasoline outlets, giving Shell full, exclusive use of the Texaco bradned gasoline until early 2004 I believe. For a year or two, Shell and ChevronTexaco have dual rights to the brand, and after 2005 or so, it becomes and exclusive brand to ChevronTexaco.
That's why all the Texaco's are converting to Shell right now, because as of 2005, they cannot use the Texaco brand name anymore on Gasoline.
It is entirely possible that Texaco will rise again as a gas brand after ChevronTexaco can use it, especially since in some parts of the country, nobody has heard of Chevron but knows Texaco (like the midwest).
Lubricating oils have a similar agreement, that both can use the Texaco Havoline brand through a certain date (ie: The Equilon and ChevronTexaco Havoline products). Eventually, ChevronTexaco gets full rights back, and there will be no more Equilon Texaco Havoline Motor Oils.