According to this all latencies improved dramatically except for SSD random read (disk seek only improved by 10x as well). Reading 1 million bytes sequentially from SSD improved 1000x and is now only 2-3x slower than a random read and for disk reading 1 million bytes is faster than a seek. Conclusion: avoid random IO where performance matters.

CPU and RAM latencies stopped improving in 2005 but storage and network kept improving.