I agree it's frustrating to see a team like McLaren put out a 10 year plan, but honestly, they really have to look at it like starting from scratch. If it was possible for McLaren to turn it around and win next year, then it's possible for ANY team to do so. We're happy with the progress Haas has made, but they're already into year three, and no one expects them to get podiums, much less win championships.
McLaren needs to start from scratch to rebuild their winning culture. I have no idea what that takes in F1, and I'm pretty sure McLaren doesn't either, nor do they have the ability to simply hire someone who does. McLaren has the same advantage that Williams does though: it is a fairly large company that relies on F1 being the marquee name that drives the business through name recognition. They can afford to linger in F1 without being competitive on track, although presumably there is some sort of limit on that.