If you have a look at these results, it becomes obvious that while absolute hard drive performance may have increased impressively, but the performance relative to hard drive capacity has decreased dramatically. From this standpoint, today's hard drives aren't as quick as old ones! Consider:

The 1991 40 MB hard drive took 37 seconds to read the capacity of one platter (26 MB).
The 1998 3.2 GB hard drive took 3 minutes and 31 seconds to read the capacity of one platter (1.6 GB).
The 1999 10 GB hard drive took 5 minutes and 37 seconds to read the capacity of one platter (3.2 GB).
The 2004 60 GB hard drive took 18 minutes and 34 seconds to read the capacity of one platter (40 GB).
The 2006 750 GB hard drive took 52 minutes to read the capacity of one platter (200 GB).

Of course this comparison is very simplified and doesn't take other factors into account, like platter count and diameter, rotation speed and average file size. Results will also vary if you take other hard drives and different capacity points. But the overall message is the same: the time it takes to fully read or write from or to a hard drive has gone up substantially in the last 15 years.

Acquiring and merging also hit the HD market. Maxtor bought Quantum some years ago and by the end of 2006 Seagate will finish its acquisition of Maxtor.