The new RDRAM had an advantage of transferring data on both the rising and falling edge of the clock and this double data transfer meant that it had a higher bandwidth than SDRAM. However, RDRAM was significantly more expensive than SDRAM due to a number of reasons.
Increased manufacturing cost from its complexity, warmer operation that necessitated memory heat spreaders, (something that would become the norm in modern memory modules) and increased latencies would hinder the adoption of RDRAM, especially since latency turned out to be the bottleneck for applications then, not memory bandwidth.
The reception from the public was not too welcoming for RAMBUS and RDRAM. This was not helped by a price fixing deal between major memory manufacturers from 1999 to 2002. This cartel included all the big names in the industry, like Infineon, Samsung, Hynix, Micron, etc and while the actual reasons were never revealed, forcing RDRAM out of the market by pricing it out of consumers' reach with relatively inexpensive SDRAM was mooted as a possible reason. In any case, the companies were eventually punished for their actions, though by then, the RAMBUS technology would be dead in the mainstream PC market with even Intel abandoning the technology by 2003.