Quite likely, but the transfer throughput is required in bursts, not necessarily continously.
Let me put it this way: what I care about is how quickly data arrives after a bunch of shader threads request it. Throughput is one way for hardware to reduce that time. The other way is to hide the latency (GPUs do a lot to keep themselves busy while waiting for memory), but those strategies can only do so much.
Lower memory throughput almost always leads to a longer runtime of GPU calls in practice, and thus lower update rates.
