I knew I would get a comment like this.
Do we really think there are ten of thousands of nodes not accepting connecting being spun up in secret? Or can we go with the simpler explanation of not many people are bothering to spin up a node and we shouldn't be making it harder to do so because at some point it may or may not be a problem.
Yes because that's the default behavior. In order to accept incoming connections, you need to configure your router to allow incoming connections to port 8333. Most users aren't going to or don't know how to do that. Not to mention the fact that there will be people running Bitcoin Core on computers where they can't control the router to allow incoming connections. Additionally many people run Bitcoin Core on laptops, and given their portable nature, aren't usually set up to accept incoming connections.
Samsung SN550, if a QLC drive causes it to take 4 weeks to sync something is really broken with the network. But like I said when I manually added a bunch of nodes that had either TELUS or Google Fiber as their ISPs my sync time dropped to 40 hours. Slowly as they disconnect and I go back to the 8-9 nodes my sync time goes back to 3 weeks.
Sorry you are correct WD SN550 not Samsung. I have a gigabit Fiber to the home connection and my sync speed jumps like crazy when I manually add nodes so I don't think they are throttling.
That does sound like a network bottleneck for you, however just increasing the number of connections won't necessarily solve the problem. You have specifically connected to high speeds nodes, there is no guarantee that just an increased connection count would have your node connect to those.
How are you connecting to those nodes? It should be possible to make the connection type one that Bitcoin Core connects to automatically if the connection drops.