Agreed. There are so many fundamental differences that it becomes wired to focus on an assumed similarity. First of all Gold has no Gold emission. There is a finite amount of gold on this planet that could become extracted. First I wanted to say that the difficulty of extracting gold doesn’t become easier again if gold mining would stop for a few thousand years, but I’m not completely sure…
But an other guess on BTC. If for BTC the low coinbase reward becomes a problem that fundamentals “need” to change. I would prefer an other change. I would take the block reward from the oldest unspent output. The oldest outputs have high probability to be lost coins. And if not, that is an incentive to spend them and prove that they are live and compete by paying fees. That would also solve the problem of unknown loss rate.