Good actuarials can pull this off. They just charge enough that they can invest some of your upfront payment and use the interest to pay the staff to support you. We know how often hard drives fail, so you just ensure that you have enough interest to replace them when that happens.

If you are the only one paying upfront this is impossible as your harddrives might fail early, but if there are 1000 people willing to pay upfront we can easially handle that.

Note that I would not be surprised if this was just a Ponzi. That we know how to do this doesn't mean we are.

The answer is: they don't. It operates similar to a ponzi where they need a certain amount of new "investors" each year to sustain their scheme.

Obviously, collapse is inevitable on a long enough timeline for any company, but this scheme in particular is very vulnerable to a couple slow years in terms of sales.

Invest it?

They get to depreciate the equipment, deduct electricity and labor, and get bulk rates on equipment.

And show mark to market accounting, cash flow and revenue for investment funding