TCO is not that important in most cases compared to finding out what to build and estabilishing the user base and not failing due to slow iteration speeds at the beginning. If it takes off, the value derived from the software is tends to be more than the cost, so discovering more things to build is better than optimizing sw expenses at second half of the lifecycle.
Of course there are exceptions, sometimes the potential upside delivered by the software is small and capped and the requirements fixed in advance, and implementation path is well trodden...
Of course there are exceptions, sometimes the potential upside delivered by the software is small and capped and the requirements fixed in advance, and implementation path is well trodden...