Does the Ubuntu community host meetups where people can come together, discuss their doubts and rectify problems with their installations? If yes, where are these announced? And if no, is there any specific reason that it is not happening?
Yes, community events to discuss Ubuntu, get installation/upgrade help, and generally collaborate are announced at the Ubuntu LoCo Events page.
In terms of focused development effort, that happens at platform sprints and the Ubuntu Developer Summit (UDS), which are announced at the Ubuntu Summit page. There isn't much installation troubleshooting happening there, though.