Selling your original system for $200 when getting the mid-gen upgrade isn't a deal. It's economics. If Stadia offers up yearly subscriptions for a lowered price, I'll factor that in when they do it. I'll also factor in lowered console prices, whenever the PS5/XB2 get their first price drop, instead of speculating on potential future price drops. We shouldn't be factoring in any price drops for either side until they are announced. That's only fair. Refusing to accept someone else's epistemology =/= moving the goal posts. You just ignored the extra internet cost for Stadia. I realize that not everyone will need to pay extra for internet, but not everyone needs to pay for XBL/PS+ either. So we can either keep the extra internet cost for Stadia, and keep the XBL/PS+ cost, or drop both of them. Either way the price of the consoles come out on top. You also ignored the cost of losing games you paid for, as well as the inability to resell them. And let's be honest, losing games you paid for is inevitable, when it comes to a streaming service. There's no speculation there.
At this point I am pretty sure that you have the clear goal to arrive at the conclusion that consoles are cheaper.
As for losing games, there are games taken down from console marketplaces too. Lots of people buy digital console games which can't be resold. You use a very subjective perspective for your analyses when the concerns you raise don't look like concerns for what will soon be a majority of PS and Xbox consumers. Digital ratios of game sales have been steadily growing and are commonly exceeding 30% by now while online multiplayer games are approaching 50% already. That's a trend of proper game ownership ceasing to be an important factor, so Stadia doesn't face a significant disadvantage here.