Yikes, that has to be 40k, at least.
In your case, profitability isn't something to consider because you've already got the drives. What you'd lose is anything extra you'd purchase and the time you'd invest. We're under lockdown here so I pulled out a couple of old 250gb laptop drives just out of sheer curiosity. At current prices, each reward of 2 XCH is ~200k INR after taxes. The power costs of having a few drives spinning is negligible even if I left them for a couple of years.
If I had a graphics card, I would definitely be mining with it whenever I'm not using it. But investing in graphics cards for the purposes of earning from them, it just seems so wasteful, the ROI for gpu mining was never great at any point. A long time ago, a shopkeeper that imported clothes by the shipping container told me that he kept 98 rupees out of every 100 earned. GPU mining never came close to this. But Chia looks like it might.
And yeah, it is eyebrow-raising, at the high price that Chia launched at. I don't know anything about the people behind the project, but everything I see so far is way too polished to be something out of a grass-roots effort. Especially the documentation/wiki on github and how well established and reputed publications like storagereview.com have embraced it.
As for shortages, they're already here. Amazon is out of stock of every desirable high tbw nvme ssd and every external drive that can be shucked.