My main reasons for why Austria has gone down this route are that:

1. Austrians are generally very chill apart from Vienna. They have that "Is ma wuaschd!" (I don't care!) mentality and are lazier than most to stand up against injustice.

2. Some right wing Austrians have mastered the ability to mask their political views. They would say something mainstream when publicly being asked about their political views but nothing straight up outrageous as they want to keep a positive image in the mainstream. They don't want to let everyone know their views but rot the apple from the core. You only get to know their true colors at the bar table (after some drinks even) or behind closed doors. I had personal experiences where folks was acting nice towards foreigners / LGBTQ+ but as soon as they left they'd go on a rant or make fun of them. And you just awkwardly look around and search for people who are doing the same and depending on how many other folks you see you'd interfere or find an excuse to leave early, mumble "oaschlecha" (assholes) and never come back (unless you really have to).

3. Austria wasn't punished or humiliated nearly as hard in WW2 as Germany. They forged the victim myth in which Austria was the first victim of Hitler's and the Reich's ambitions. They brushed off the fact that the Wehrmacht was met with cheers from the locals as them not wanting to look suspicious and being deported. And since Austria came away with it and didn't lose anything except them having to be neutral by law (an agreement made with the Allies and the USSR so Austria won't be split up like Germany and Korea) they never really had to tackle the Nazi issue in their population. Over time this developed into a very Anti-German sentiment up to the point where Austrians consider themselves to be better than Germans because "Hitler became the 'Führer' in Germany whilst he didn't even become an art student in Austria. He would have never made it here." I remember an interview with a Kickl supporter in which she was asked the question wether she thinks that Kickl or the FPÖ were Nazis and she replied that she doesn't know what makes you a Nazi since "it was never taught to us" (of course kind of a stupid excuse for being illiterate in history).

4. Similarly to the AfD, the FPÖ has seen that social media is a great propaganda tool. They were arguably the first to use Instagram and YouTube ads and now pump out TikTok propaganda. This propaganda is being consumed by people with no/low critical thinking skills and they then consider themselves politically informed. Even worse the constant emotionalization makes them think (rationally) even less. This is why the FPÖ has slogans like "Your heart says yes" because they don't want their voters to think with their brain, they just want an emotionalized, radicalized mass that is not questioning what the FPÖ is doing. And they are helped by the tabloids which sadly make the vast majority of Austria's consumed press. They can be found everywhere since they are "free" and the masses take them and when they are finished they just leave them and so they spread literally everywhere. Now those big tabloids are usually owned by some rich dude or a consortium of rich dudes who think that neoliberalism or even anarcho-capitalism is the way to go (for them). So they are happy to influence their editors to write on topics that suit the AfD's, FPÖ's and even ÖVP's views and in return those parties make economic politics for the upper class. This isn't really considered corruption since in many cases money doesn't flow but it is more like a symbiosis.