I gave him a 'D'. The only reasons it's not a 'F' are:
-The BC program was a good idea
-They lucked out for a moment with good Series S sales during pandemic lockdowns
-They acquired Zenimax (in due time I think this one will generate more ROI in terms of games & money vs. cost than ABK)
-He's got a slick mouth that ropes in tons of Western gaming press and "influencers" to repeat his talking points to control discourse online despite reality
-The One S and One X were good pieces of hardware
-The Series X is a good piece of hardware
-There have been some good games from them over the past 6 or so years (Flight Simulator, Cuphead, Ori 2, Forza Horizon 5, Sea of Thieves now in its current state)
However, he has ultimately failed at being an effective leader for a console platform brand as seen with Xbox's dying sales globally not just in hardware but also software (which I'd posit is the
real reason for the multiplat push; 40-something million lifetime hardware sales wouldn't be an issue if attach rates in software sales/revenue were large enough). He failed to spearhead enough industry-leading, mass market-appealing 1P games to drive interest in Xbox consoles. He pushed for a Day 1 PC strategy that undermined the value or importance of their console in the market.
He pushed for Game Pass, a solution in search of a problem, which conditioned sizable chunks of remaining hardcore/core Xbox enthusiasts to either not buy games, or buy them very cheap. Meaning the Game Pass model undermined the B2P sales market for the console among a big chunk of the gamers who'd do the most B2P spending otherwise. Those who didn't remain on Xbox moved to platforms like PlayStation and, especially, Steam, taking most or all of their spending dollars for 1P
and 3P games to non-Xbox platforms (a cautionary tale for Sony/SIE if they are considering a continued PC multiplat strategy with no changes or with more aggression in porting cadence).
He was forced to buy large 3P publishers to make Microsoft gaming relevant after big IP like Halo and Gears were seeing major declines, and leaked emails/internal memos showed their intent with M&As was to leverage parts of MS with real profits to buy out as many 3P as possible to isolate Sony in severe foreclosure strategies, likely with various shades of anticompetitive practices laced along (predatory pricing, price-fixing, price-shifting etc.) to aid in this. The fact they've seemingly 180'd on this is less out of their own desire, and more because regulators forced concessions making the original strategy nigh-impossible to carry out.
All of this happened under Phil Spencer's leadership and if it wasn't for the good points I listed earlier, I'd easily give him an 'F'. But those bright spots salvage his run as head of Xbox, if only slightly.