This is part of my e-commerce business. (I do some regular items as well but discontinued items are often lucrative).
See e.g. https://www.amazon.com/Motorola-H720-Bluetooth-Headset-Packa...
Two years ago this was going for $23.50 wholesale (I was offered by a large supplier) and $35 retail. Tens of thousands of units sold. Price went up over time and whoever still has units is making a killing now.
It's definitely possible to deploy millions into the business, but it's far more of an active part of a portfolio. You can't trade an index of discontinued products that appreciate.