That's actually a great explanation. The concept of good and bad debts is actually refreshing to read and understand. It makes sense to have debts if you know that the overall value is going to be positive from those debts. It's similar to a businessman taking loans from bank at let's say 10% and easily making 20-50% profits from the same money, then that's good debt.
That said, it's not easy to actually identify whether your plans and calculations are going to be viable because there are hundreds of other aspects we won't account for when making the calculations.
That is why people do not take out those loans that easily, because there is no guarantee in life that you could make a profit from that debt. I mean if it was just that simple, lets assume that you take out a 20k loan, pay maybe like 1k per month for 24 months (thats quite high interest in most places) and then you just buy GPU's with it, and start mining. If you can find those GPU's at a sale price, and have low electricity, you should be making profit and that loan should be nothing to you. But we all know that it is not that simple, your GPU could get broken, your house can caught on fire, ETH could publish 2.0 out of nowhere and a million other things.
This works on any idea, you could take a loan out for your factory that makes a lot of money, and want to make more money and use that to buy more machines to produce more and earn more, then you could end up living through a pandemic and fail to pay your loan back because your business just went bankrupt basically. You could buy a house, and make a lot of profit from that with that mortgage paid by the person who pays the rent, but then housing market could crash. All in all it is very difficult to predict what will happen.
However, "debt is bad" should not be the way out, bad debt is bad, good debt could be good or it could turn bad in a case of emergency like I mentioned, but at least you tried something with it, and can't say I never tried.