You can have an efficient computing system, centralized databases or banks.

However, they can be manipulated at will by a centralized authority.

Now, if you want no one being able to manipulate it, you have Ethereum.

What underlying serious societal problem are we solving, though, really? Was the world awash in crime resulting from fraud via database manipulation?

Yeah, I'd like to know the answer to your question too. The original Bitcoin whitepaper proposed the decentralized ledger in order to enable Bitcoin transactions. But somehow that got warped into decentralized ledgers being the cure for all that ails the world.

Not to mention whatever fraud crypto might prevent is replaced by an entire fraudulent industry.

How does the Raspberry Pi comparison factor in to your quest of understanding the fundamentals? How is that metric relevant to the fundamentals?

I mean, if that's a fundamental point to be made, shouldn't you be able to purchase a machine stronger than a Raspberry Pi and take over the Ethereum marketcap? Maybe you can charge less for gas and win marketshare that way. After all, people are paying for the Raspberry Pi processing power... right?

I've been a computer programmer for 40 years so I'm interested in the computing parameters of the machines I run

Not the parent, and not knowledgeable about Etherium.

But does't such limitations fundamentally question the global ambitions of Etherium? Could you really run a global digital economy with such limitations?

To me it seems an apt analogy about the capacity of Etherium, assuming it is correct?

It's all sorts of incorrect, incomplete and misleading.

It also invokes the corollary that this virtual computer weaker than a Raspberry Pi is the most efficient computer processor on a realized dollar basis: what other computing system with less processing power than a Raspberry Pi is settling $10 billion dollars of finance per day?

It is settling 10 Billion dollars per day... barely. I don't think anyone can dispute that Ethereum network is buckling under the pressure (represented by rising gas prices). I am not sure if OP was trying to be snarky, but they do have a point. This system is not scaling well and the problem is how slow EVM is. It is valid to criticize that and I think this has even the insiders worried.