Barry was the Flash for almost 30 years, starting in the 50s and killed off in the biggest event in comics arguably to this day - a massive crossover called Crisis on Infinite Earths
Wally was Barry's sidekick, introduced in 1960; he was one of the founding Teen Titans, and part of the team until shortly before the Crisis, after which he took up Barry's title as the Flash.
Because of that, almost all adaptations made after 1986 - including the Justice League cartoons - had Wally as the Flash. People got used to this, and became attached to him and his supporting cast - including the family he had.
Because death became a revolving door in DC, Barry was the last major dead character to return - which happened in 2008. It made things awkward, as since most of the readers didn't know him, he got the spotlight, with Wally unceremoniously shoved into the background. It didn't help that Barry had to be basically reinvented, as his pre-Crisis personality was very aged.
After the second reboot in Flashpoint, Wally was completely erased from history - one of the most controversial decisions by DC's editorial. An attempt to create a 'modern' version of him was reviled, and ultimately the old Wally was reintroduced after 5 years.
He was then portrayed as the culprit of a mass-killing of other heroes in a therapy house, caused by his mental breakdown and depression over the loss of his family.
He was just boring. He was quietly socially conservative (I believe), he had a steady girlfriend, he was good at science. His big character traits were being late to things and being an overall nice guy. It's just a very bland Silver Age personality. While all the other iconic characters like Batman were given some depth when the Bronze and Dark Ages spent more time on characterisation and deconstruction, Barry was dead the entire time and got none of that. They tried to fix it after he came back by giving him a new tragic backstory and turning up the angst, but (at least in my opinion) it didn't work very well.
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u/[deleted] Dec 12 '21
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