Success in one generation never, ever guarantees success in the next generation. I think Microsoft thought their market share would continue to grow automatically, regardless of what they did.
As for the Xbox One, we have to wait and see what happens with Pro vs. Scorpio. Will the market go for pure power or does the cost-to-performance curve still apply even for these "premium" boxes? It's going to be interesting.
If we're really headed for a "generation-less" future for consoles then it's going to be a constant back and forth struggle. Right now, we're about to see which approach regarding mid-generational upgrades works best.