That is exactly what you need to be thinking about. As much money as Microsoft makes on consumers backs and then they lay these traps for would be small business developers. There's a reason why rich people try to avoid paying for their lunch.
Yes, you should be thinking 3-5 years ahead. And if you're thinking that far ahead, you'll amortize the free 3 years with the 2 years after in which you pay and come out with a true cost. You might even work in the odds that you'll be in business and/or have sold out in that time along with some estimate of switching costs to other technology (which might actually be low if you mainly use Azure).
I don't know if it still comes out as worth it, but that's what you have to figure out. A kneejerk "I'll be paying for this in 3 years so I shouldn't take advantage of it being free now" isn't exactly the most rational response either.
I get the general feeling, but VS licenses are not what going to cause your startup to go bankrupt. People's salaries are an order of magnitude bigger, to say the least.
That is exactly what you need to be thinking about. As much money as Microsoft makes on consumers backs and then they lay these traps for would be small business developers. There's a reason why rich people try to avoid paying for their lunch.