elbert :
I think WD is closing drive manufacturing plant to keep prices high.
This is a common misunderstanding of how economics works. If there is sufficient demand, a company can make more money by producing more items to sell. The marginal cost for the extra production is less than for existing production (cost to produce the 2 millionth drive is less than the cost to produce the 1 millionth drive), so the profit margin on the extra drives is higher. The only reason a company (without a monopoly) will willingly reduce production is if there isn't sufficient demand.
A company can only make more money by keeping prices higher than market price if it owns a monopoly. If there is no monopoly and a company keeps prices high, buyers will simply buy a competitor's product instead, and the company will put itself out of business.
The HDD industry in particular had some of the slimmest profit margins for decades (like 1%-2% vs about 5% for the computer industry as a whole). That's what led to the rapid consolidation of manufacturers in the 1990s and 2000s, and led some big name players like IBM to exit the business.