You're arguing the point that because his help wasn't needed in the end that he shouldn't have offered to help.
But it's conceivable that his expertise could have been useful.
Did any other organisations offer subterranean expertise? Genuine question, e.g. mining companies, drilling, or was it just that Musk made the most noise about it?
My impression was that this was not a good-faith effort to help but rather to be seen to be helping, without any concern for whether his efforts were useful.
Which is itself a bad faith evaluation. I'd prefer to be kinder and thus keep the door open for other such "help" in the future. Fundamentally, he didn't do any harm.
Actually, I believe that other people were exploring the options of drilling a rescue tunnel from the surface. IIRC, there was even the beginning of projects to make a usable tunnel launch site for such a rescue tunnel.
The expertise you'd want for drilling an emergency rescue tunnel would be a combination of skills related to drilling roughly pipe-sized vertical shafts [1] (mining/oil services, or maybe the companies themselves; I don't know what the exact breakdown of work packages end up being) and remote (specifically mountainous and jungle, in this case) infrastructure and logistics, which is military or again mining/oil services. Possibly a geologist or two on hand to assess the rock layers and identify hydrographic hazards as well as risks such as accidentally causing cave-ins. For the cave diving extraction, you'd want experienced cave divers, ideally ones with good first aid knowledge and cave rescue experience. For any further expertise, I wouldn't suggest anything without hearing the observations from the cave divers who have just explored the cave themselves.
There is no evidence presented that Musk, nor any of his companies, has any of this kind of useful expertise.
[1] Emphasis here on vertical shafts. There is a world of difference between a tunnel-boring machine that tends to remain within a single geological stratum and a vertical shaft that is constantly cutting through several strata of different kinds of rock (that require different cutting techniques).
But it's conceivable that his expertise could have been useful.
Did any other organisations offer subterranean expertise? Genuine question, e.g. mining companies, drilling, or was it just that Musk made the most noise about it?