While investors like optimizing money makers, they certainly need to see some large future investments as well to get excited about. Otherwise you live and die only on the quarterly results. Chapek clearly died with that last quarterly report. I think that ultimately the Board/investors saw there was nothing Chapek was looking at as a long-term strategy, just cost-cutting and price gouging to the limit on Disney's current big money maker: parks. But there is nothing in the pipeline there, nothing to keep investors engaged, it's all wait patiently for a few years before Disney+ supposedly turns a profit. Very perilous way to run a company whose main competitor in their actual moneymaking industry is seeing record profits and a massive theme park on the way.
With weakening demand in the parks evident and streaming's stock boost no longer a premium it was time to quickly cut the cord. Streaming-wise, Disney is in a solid position with the amount of subs, but they desperately need price increases (on the way) and cutting back content costs/shifting movies back to theatrical.
It's completely obvious, but Iger is miles better at the actual back room dealing than Chapek and is completely willing to make splashy purchases/investments to build excitement among investors. Think his priorities are likely:
1. Try to get theatrical/streaming mix back on track. The mix is off, and it is clear that too many movies that could be decent hits theatrically are going straight to D+, which has very little value add compared to a TV show.
2. Do everything he can to use his connections to get China back in the fold and repair that relationship.
3. Appease the parks fans with some rollbacks of Chapek-era initiatives (convinced the actual moneymaking stuff won't be cut like Genie, but park reservations will be axed, park hopping anytime will be reinstated, etc.) and announcing some big investments there to generate excitement both among fans and investors.
4. Look for another big potential purchase, could be another studio/streamer.