First, thanks for sharing that cool chart of BRK vs SPY. Really tells a long story in a short glance.

Trying to read the end-points from the graph, I get a 1.7% TOTAL - not annual - win for the SPY over 20 years. (Jim probably has more accurate numbers.) I personally find that a rather remarkable performance by BRK given the difference in risks taken for the reward received. And it's all happened since circa 2019 with the big tech stock explosions.

At today's prices I'd far rather hold BRK than SPY.

Not a critique of your post - just my viewpoint.

Munger taught us to adjust expectations. For myself, I'm reminded of an old expression: "What do you want, an egg in your beer?" From a Google search I find it to mean:

“Egg in your beer” as phrase, rather than a drink, generally denotes getting something for nothing or having/asking for too much of a good thing. For the WWII context, this makes a lot of sense – both eggs and beer were relatively-hard-to-come-by for soldiers, so combining the two would be asking for an awful lot.

I'll be very pleased if BRK performance continues to match the SPY long term. I'll sleep well. And I love the potential for a step-up in value for my heirs.