I suspect we will see the PC/Tablet market largely move to Flash with HDDs being used for backups, media servers, and mass storage. As Frank so succinctly points out, price is a significant factor and will continue to be for some time, especially at terabyte and petabyte levels.
The only problem with the CRT analogy is that what replaced CRTs quickly came down to comparable, mass-market-friendly prices...otherwise the death of the CRT would've taken much longer.
selinz recently paid $79 for a 2TB hard drive. How much flash can you buy for that price? How many years will it take before the price difference per terabyte (by then it will be price per petabyte) between hard drives and solid state memory will be insignificant?
Does this even matter now? Yes, there are a lot of HDD made and sold still, but there's likely only a decade left. This strikes me as would a discussion of the top-two CRT manufacturers back in 1999 or 2000.
I'm not saying that HDDs will disappear. But they will be gradually forced into niche markets that require maximum capacity or some other attribute specific to rotating media. Okay, I am saying that they will disappear. They'll be forced into those specialty niches and then before anyone notices, they'll be gone altogether.
The important discussions are related to solid state media. Who is leading in the technology and price curves and who is likely to have the lead in the coming decade. For that debate, Seagate and Western Digital are far from the only players worth analyzing.
Most all of the increases in Market Share have come at the expense of Seagate. Seagate still has a robust line of SAS, Fiber Channel, and other enterprise storage but it has lost (for now) the confidence of integrators of their consumer lines.
After the Seagate nnnn.10 line and continuing into the nnnn.12 line of consumer integrated drives the failure rate has been much higher than their previous drives and most importantly, their competitors.
The same thing happened to Western Digital in their 1.4GB - ~8GB drives, it was not IF the drives would fail during their warranty period but WHEN. Seagates Market Share benefitted from that debacle (especially to WDs Silence on the issue as well as the contractual silence of their huge market integrators) for years.
Sorry Seagate, I was an avid (maybe even rabid ;) follower in this space (Seagates NS vs WDs RE3 & RE4 RAID lines) but if I were to have to buy today You would have to convince me that I would not have to go through unnecessary rebuilds and have an ongoing RMA ping-pong relationship.
Well, I have indeed noticed the preponderance of WD on the low end of the spectrum at our local electronics superstore. That does seem to be a good indicator. I got a 2TB drive for $79. The big question is can they make money at that margin?