And your "garage sale tip" is bullshit of the highest order.
I completely agree. It is bullshit of the highest order. There is a special IRS term for "bullshit of the highest order". That term is "business".
If you've done it, you are lucky you haven't been audited.
If I had done that, and I was audited, and the IRS had a problem with it. I'd owe what I would have owed anyway. Maybe with a small penalty.
You can't deduct on a loss every year without being classified as a hobby.
How many companies do you need me to name, and how many years do they need to show losses? You certainly can show several consecutive years of losses. You'd be hard pressed to find a company that hasn't shown many consecutive years of losses. Lack of profit doesn't mean a business is unsuccessful. It means they paid out their vendors and workers and creditors a bit more than they brought in.
And why do you assume you will always show losses? Why do you assume you won't find a profitable niche in the process? The only requirement the IRS needs to classify you as a business is the fact that you don't make an assumption like that. That assumption is what makes it a hobby. Don't make it, and you're a business.