Southgate was always going to step down as England manager after the Euros whether that was going out on a high by lifting the trophy or a low by losing in the final. I am glad though that it was left to Southgate to make his own decision though.
However, I agree with both @Robbie and @Wheelbarrow repair man both make very good points. Southgate just never got the job done despite falling on the easy side of the draw once again. I'll give Southgate his credit for getting us to these stages but with the squad at his disposal, we should be expected to reach these levels. The only exception was the 2018 World Cup where we over achieved. Even then it was a missed opportunity.
World Cup 86 - England lost to an Argentina team with Maradona. Both goals should have been ruled out.
World Cup 90 - Lost in the semi final to Germany on penalties.
Euro 96 - Beat a Netherlands team 4-1 that consisted of Van Der Sar, Kluivert, Seedorf, De Boer, Bergkamp. Lost to Germany in the semi final on penalties.
World Cup 98 - Took Argentina to penalties playing with 10 men for 70+ minutes and having a goal wrongly disallowed by Sol Campbell.
World Cup 2002 - Lost to Brazil (R9, Roberto Carlos, Ronaldinho, Rivaldo, Cafu)
Euro 2004 - France (Zidane, Henry, Trezeguet) Lost to Portugal (Rui Costa, Deco, CR7, Figo) despite having another perfectly good Sol Campbell goal disallowed.
World Cup 2006 - Lost to Portugal (Figo, Rui Costa, CR7).
These teams, especially the golden generation, were considered failures. Even despite managing to go toe to toe with some of the biggest teams around.
Even when you consider the level of opposition in the tournaments Sam Cunningham mentions in @Piethagoram post. Germany in 2010, played both France and Italy in 2012, Italy and Uruguay in 2014. The only inexcusable one was 2016.
Southgate's England in 29 games against teams ranked in the top 10 of the World Rankings have won just 7. In the last 3 tournaments when they've come up against the bigger teams, we've lost. Italy in 2021, France in 2022 and Spain in 2024.
I'm all for the media and fans praising Southgate for what he's done in terms of harmonising the squad and fans, bringing the unity back to the Nation after hitting rock bottom in 2016 and reaching the stages he has but there needs to be perspective when claiming Southgate to be the best manager since Sir Alf Ramsay. Especially considering only Sir Bobby Robson (since Alf) has managed England for as long as Southgate has. But, back then the Euros only consisted of 8 teams rather than 24 that is today.
Southgate's England have not come up against top level opposition like previous teams. It's been relatively straight forward or at least easier than previous tournaments. Even so, we came close to messing that up against Slovakia.