Well explained Dolcca

Yes torrents tend to be most active when they are first uploaded and then in time people need the hdd space for new files and things become unseeded. You can request a reseed by clicking the request reseed text link button on torrent description and maybe someone still has it and adds seed if you are lucky.
If you grab it your ratio will not change directly. It is only counting the actual downloaded amount, so if you start a download and there are no seeders no ratio will be affected until someone seeds it.