All expectations have no proof? Yes it's speculation.
Re: evidence. The evidence we do have is from precedent - former file sharing services that have made money from similar types of technologies (notably bit-torrent). It is an established fact that money can be made via advertizing and given both that CPUs are terrible at mining cryptocurrencies and that it would dramatically degrade performance the bitcoin suggestion is unlikely.
Agreed that it is speculation. But this is what the OP asked for at the top: speculations as to why the developers would invest in the project.
RE: costs being relatively low. Agreed. Revenue from ads are similarly small. The calculus is performed at scale - which is exactly what this technology hopes to be. The relatively low costs are what makes large margins with advertizing possible.
Re: evidence. The evidence we do have is from precedent - former file sharing services that have made money from similar types of technologies (notably bit-torrent). It is an established fact that money can be made via advertizing and given both that CPUs are terrible at mining cryptocurrencies and that it would dramatically degrade performance the bitcoin suggestion is unlikely.
Agreed that it is speculation. But this is what the OP asked for at the top: speculations as to why the developers would invest in the project.
RE: costs being relatively low. Agreed. Revenue from ads are similarly small. The calculus is performed at scale - which is exactly what this technology hopes to be. The relatively low costs are what makes large margins with advertizing possible.