On org-roam there's also no quick way to get started and the install instructions look like this: https://www.orgroam.com/manual/Installation.html#Installatio... so it's not really a surprise that's it not going viral and being used by everyone.
To borrow a phrase from discussions around Dropbox, this most definitely is a feature, not a product.
But I think it's too early to call roam, the startup, a success. It has some mindshare, but the product has no defensibility. It's not that complex. A competent developer can probably build a clone of Roam in 1-2 months of full-time work. A lot of copycats have started already and I wouldn't be surprised if in a few years it's not Roam that has won but just another copycat that had a better UI. Kind of reminds of how Slack killed that other app before it... was it... hipchat?
The takeout option lets you download a copy of your files at any time but they also often have sync issues, etc. As far as I can tell, they make heavy use of local browser storage which syncs to a cloud back up. People keep seeing data loss (or did when I stopped following them) when this connection fails. Is it growing pains? Yes, probably. Is it right for me when this risk can lead to data loss and not just a conflict resolution process? No.
I do wish them luck and am looking forward to the various local clones getting better (org-roam, Obsidian, etc... no shortage).
Personally I'm not a fan of the company, culture, and the cult-like following Roam has. I hope somebody else succeeds and takes over the market and I'll move there. But so far roam is the best life/knowledge management app I've used, and I've tried a lot of them.
The core idea is literally bolting backlinks on top of Workflowy. How is it you can make a business out of that? How is it that the idea is only now reaching viral popularity, even though its a rather obvious concept that had various well-known incarnations in the past (e.g. automated "pingbacks" on blogs in the 2000s), was fully conceptualized into an even better idea all the way back in the 1970s (Xanadu's transclusions), and probably traces its lineage all the way to ancient Sumeria. I sometimes don't understand the lifecycle of ideas and tools in our reality.
(That's not a jab at Roam Research folks. I congratulate them on building a successful piece of software. Though I'm not going to use it anyway, because I like to own my data.)