Microsoft wants everyone on 10 as they are planning on developing things for Windows 10 specifically. Notably, they are trying to get Xbox games be developed in such a way so that they work for both Xbox and Windows 10. They probably have other things in the works besides that. I do not like the things they are doing to force people to upgrade though. Dismissing an upgrade window should not be considered consenting to the upgrade nor should forcing the user to dismiss or delay the upgrade every few days or so.
If you wish to stay on windows 7 I would recommend grabbing never10 to stop the upgrade from occurring. If the upgrade happens, you are able to revert it but only for the first few weeks I think.