While I agree with the sentiment of what you've written to the new owners of HERE, I can't help feeling there's a distinctly anti-OSM vibe from this piece. It seems like you're suggesting that HERE's data might be opened up to external contribution ("It would certainly reduce your ongoing data collection costs") as a competitor to OSM, which would only serve to fracture the open data community.
There's already several other projects in the global, open geographic data space; Natural Earth, openaddresses, etc... which receive attention from the global open data community, which arguably compete with OSM. Competition is, generally, good and healthy and increases diversity.
However, it seems to me that the point of the "open data revolution", and what we should be pushing for, is the opening up of a high quality, global geographic dataset and the growing irrelevance and devaluation of proprietary geographic data. What I think we need to be very careful of is what traditionally happens to the political Left; that despite lip service to "solidarity", they expend their effort fighting amongst themselves (as parodied by Monty Python's Judean People's Front sketch) and concentrating on the small differences between them rather than the large one separating them from the Right. One day, soon, when "open" has won, we can afford to split our communities and duplicate our efforts. Until then, all the time we're advocating a plurality of projects, we're helping proprietary data last a little bit longer.
Regardless of whether they actually would open up the data, and we've no reason to believe that they could or will, it sounded like you were advocating for the first true "competitor" to OSM. Which, at this stage, would only help Google / TomTom. You're right, it'll happen eventually, but I had hoped that Google, Apple, MQ, etc... would be using and contributing open data before then.