I think it really depends how much time & energy one is willing to put into something.
As far as politics is concerned, do most people individually have a say? No. Not really. Hundreds of millions of people reduce individual voices to a wash / dull roar of popular sentiment. HOWEVER, anyone who is willing and able to devote themselves to a cause? Can both do so, and rise within the ranks until their voices do matter*. Until they are affecting policy and making a difference in one way or another. Whether that's locally, regionally, nationally, or internationally.
Far from just talking about the elected officials, although that's one avenue, it's not for everyone. There's also their staffs, lobbyists, lawyers, journalists, judiciary, high ranking military/ StateDep/ Department of _______, etc. So, whether from inside the power circles, or outside of direct access, but still influential to greater or lesser degree.
That's the beauty of a free society, IMO. The ability to choose where we want to direct our energy, and the easy movement (comparatively) within those circles.
That's not saying that the competition isn't fierce, -more in some areas than others- but there is competition. Every single area of government & associated fields, are self selecting. So if one wants to have a voice in how things are run? Whether it's the local school board or whitehouse staff, local reporter to international news syndicate, established judiciary or a watchdog group (like Human Rights Watch), LOL. Including rising within the ranks of mega corporations and other heavy presences in politics! ... Hundreds and hundreds of avenues for people to pursue, depending on their own desires & talents.
In destabilized or dictatorial governments... That's simply not the case.
* That a person has to work hard, be good at what they do, and have pretty decent luck and timing... Doesn't negate that each and every single person making decisions (from the POTUS to the local City Planning Commission) got there by choice. By deciding they wanted their voice to matter, to have a say in how things are done, and worked for it. Just wanting it isn't enough. But it's a start!