That's not generally true for SSDs, especially if NCQ is supported. When swapping in latency is usually more important than throughput, so you would want to only swap-in what you need. Maximizing thoughput by reading stuff you don't need is slightly silly.
With write-out 8 channels * 4 NAND chips per channel * 4KB page size = 128KB should be enough to get max write throughput (less for SLC). Buf if you're swapping, you're generally also swapping in, and writing a lot data will kill read latency, so you might want to limit the writes anyway.