Launch day (or even post-launch) sales numbers aren't a focus for Microsoft anymore, which is likely why their marketing has changed so much recently. It's all about increasing Game Pass subscribers now, and that doesn't rely on pre-orders and launch day numbers. They wouldn't be leaving the campaign reveal so late if pre-orders were the focus like they used to be.
That said, I agree the marketing has been a mess. But 'how well it sells' will be secondary to 'how many more Game Pass subscribers' as far as Microsoft is concerned. As we know from Matt, they are literally acquiring studios purely with Game Pass in mind, not software sales.
That would be a silly stance for Microsoft to take, given the more day one sales there are, the more revenue there would be for Microsoft, and the more visibility there would be on the game, greatly increasing both future sales, microtransactions revenue, Game Pass subscriptions, online streaming coverage etc. There's really no good reason at all Microsoft shouldn't want as many day one players as humanly possible, unless they want less success and less money or something, which I highly doubt.
I think some on this forum have wrongly seperated marketing that drives sales, to marketing that drives Game Pass subscriptions. It's the same marketing that does both. The more interest there is in the game, the better the marketing, gameplay reveals, trailers, adverts, previews, reviews etc, the more copies the game
and Game Pass subscriptions it sells. A failure in marketing negatively impacts both, not just one and not the other.
It isn't even like showing a vertical slice of gameplay at E3 would have cost them any more money either. Infact, it'd probably have been cheaper than commissioning the CG trailers they showed off.