The issues you mention are some I’ve been thinking about for a while, so here’s my two cents on the topic :).
First, is RDF “hard”? I don’t think so. In fact, I think RDF is easy. I also came from a background similar to yours (I think), because I didn’t know anything about the Semantic Web and I was used to just creating an app with Laravel. But, it wasn’t too difficult to understand how RDF worked. In particular, after reading the RDF primer and the RDF Schema spec I just saw RDF as a more general way of declaring an object-oriented mental model I already had. All along the way I’ve been learning more, and I realized that some of my initial assumptions were wrong. But overall, I’d say the mental model I got on the first weeks of learning RDF still applies.
But there’s a caveat to that. RDF is not hard; but choosing a vocabulary for your app is hard, and I think that’s where the issues arise. However, if you don’t even try to be interoperable, it’s very easy to create your own vocabulary. You just create a class and properties like you would in a normal object oriented programming language.
If I don’t care about data portability, then I’m not going to use RDF, I’ll just continue to store my data in a SQL database, or a CSV, or whatever.
I don’t agree with this part, because RDF/Solid has an inherent advantage over SQL, CSV, or whatever. In Solid, even if your vocabulary is unique to your app, the data is available to users. So even if you made up a vocabulary and no other app uses it, the community will be able to start using your vocabulary, or implement tools to convert from your data to other formats, without your involvement. Using a traditional architecture, the data will be enclosed in your server and you need to implement a custom API if you want to expose it. I wrote a blog post talking about this, maybe you find it interesting: Interoperable serendipity.
Now, having said that, I would agree that it’s more difficult for developers to get started with Solid/RDF. But I don’t think it’s because it’s more difficult to understand, it’s just that the community is smaller and not many people is focusing on developer experience. I can make a comparison to PHP. I remember, years ago, that there was a joke running around that PHP was dead and everybody hated working with it. But then, Laravel came around and now a lot of people love PHP. Sure, the joke is still going around, but Laravel has a thriving community with a lot of happy developers. I think the same could happen with Solid, but we haven’t got our Taylor Otwell yet (the creator of Laravel).
Personally, I have been working in some tools in that direction. But to be honest, I’m not really doing it to contribute to the community; I’m just working in the open and that’s why I open source my code and document my libraries. But it takes me ages to finish anything because I’m just working in sideprojects and it’s not my intention to go full time on this at this point (I’ve been working in my latest Solid app for over a year now xD). In case you’re interested though, here’s the library I’ve been working on: Soukai Solid. And you can check out an app using it here: Media Kraken. Eventually, I’d like to publish a framework as well, allowing for the framework new my-project workflow that you mention. But it’ll probably take months or even years until that happens.