It seems Bitcoin Core has embraced the digital gold narrative, which fails to achieve the original goal of P2P electronic cash. Do these developers really know better?
They're developers for a reason, they can only try to optimize the throughput, improve on existing protocols and come up with better ones. We aren't economist and it is risky to make any fundamental changes to the protocol.
"I suspect we need a better incentive for users to run nodes instead of relying solely on altruism"
Money? Then who's paying for it? Taking a cut from the miners is going to discourage a lot of them from mining. Node count isn't too big of an issue, and that is certainly not affecting the goal of "P2P electronic cash". Bitcoin is still very much P2P.
Bitcoin is also important as a reserve of value to protect against inflation. It is both.
Eh, generally it isn't a good investment vehicle or an inflation hedge. It's easily affected by fiscal policies and the financial markets. The only good inflation hedge is probably precious metals.