It's hard to get high quality debate. I don't think this is a personal problem about me. I don't think I'm being gatekept for not having a PhD. People can be dismissive over missing credentials, but that's a sign they aren't rational and wouldn't be good debate opponents. I don't think having the credentials would actually get me good debates. I don't see many intellectuals having great debates with each other but excluding me. A lot of debates I see on social media are about politics not philosophy, and they're low quality and stop early. Academic journals aren't set up for much back and forth debate. Debates that take place on stages are generally too short and aren't followed up on enough, and often focus more on speaking to the audience than trying to engage with the other side.
The internet changed. Usenet is long gone. Yahoo Groups and other email lists were largely replaced by Facebook. Forums are less popular than Reddit. Reddit is sort of like a forum but significantly different because topics quickly leave the front page. On a forum, if someone posts in a topic, it goes back on top of the front page, so a discussion can continue for weeks. On Reddit, discussions rarely make it to day two. The late adopters diluted the internet and companies like Google didn't really try to preserve it. The old internet didn't solve the problem of high quality debate but it was closer and things got worse.
I used to get more debates by not asking for debate. If someone argues with you, and you argue back, they might respond. Now I often say "Do you want to debate this and try to reach a conclusion?" And they don't want to. But if I had just made an on-topic argument, I probably would have gotten another response, maybe several more. People seem to prefer non-committal, unstructured debates. But I don't. I want to try to reach a conclusion. I got tired of repeatedly going through the early parts of debates which then end midway. I don't want to keep repeating the same debate first halves with different people but not getting to do second halves. I want more of the later stages of debate that I have less experience with. The later parts of debate are inherently more varied; discussions often start in similar places (discussing standard topics and making standard initial points) but end up in different places as they branch repeatedly. The more branching points a discussion goes through, the more likely it's unique.
People who generally agree with me often won't debate even though I'm sure we disagree about some things. Some people are focusing on learning which is totally fine. But the world is full of people who think they already have the answers, so some of them ought to debate. Why debate if you already know the answers? Because when two people think they know the answers, but disagree, then at least one of them is wrong. If you're right, debating and showing the other guy he's wrong and overconfident is a good activity. In general, you shouldn't hoard your knowledge; you should be happy if other people learn, improve and partially catch up to you.
People who generally disagree with me are often dismissive. And people often only want to debate what they have direct expertise at. Bayesians usually don't know enough about Popper to engage effectively, and most deal with that by being dismissive not curious. A lot of people will debate a topic but if you question their premises for that topic then they won't debate, even though those premises are relevant to their preferred topic. Why? Defending their premises is hard and not their area of expertise, not what they're good at debating, not what they've spent a lot of time thinking about. Or they may already know a lot about three ways of defending their premises but not already know a lot about defending their premises against the specific challenges I'd bring up.
Solutions? I don't know. There are often career incentives and social dynamics making all of this much worse. The world has a lot of problematic power structures.