The 2019 Macs were vertically integrated and Apple could do NOTHING good with the Intel PowerPig i9 CPUs. My i9 once once ran down from 100% charge to 0% in 90 mins PLUGGED IN ON 95W CHARGER! I was hosting a meeting. The M1-M4 CPUs forsake multithreading and downclock and this is one of the many ways they save power. Video codecs are particularly power efficient on mobile chips!

I used a 2019 MacBook Pro for quite a while, and it was my first (and so far only) dip into Apple-land. While I appreciated the really solid build quality, great screen, etc, the battery life was pretty abysmal. We're talking easily under 2 hours if I had to be in a video call, which basically meant taking a charger to any meeting of decent length.

The 2nd biggest disappointment was when I ran my team's compute-heavy workload locally, expecting blistering performance from the i9, only to find that the CPU got throttled to under 50% (I seem to recall 47%, but my memory is fuzzy), within 6 seconds of starting the workload. And this was essentially a brand new laptop, so it likely wasn't blocked fan intakes. I fail to see the point of putting a CPU in a laptop that your thermal design simply can't handle.