Can MCTS be considered a substitute for MCSD?

Because both credentials have developer tracks, the two can certainly be considered related. But look at the requirements: you can earn an MCTS by taking as few as two exams (for example, MCTS: Net Framework 2.0 Web Applications), whereas earning the MCSD requires taking four core exams and one elective exam. Thus, I think it makes more sense to compare the MCPD, which requires earning a development related MCTS, plus taking three additional exams or adding a fourth upgrade exam, to the MCSD than to compare the MCTS to the MCSD.