I never said the netcode was perfect, on the contrary. Actually it seems to be more buggy than ever, so obviously there is a lot to fix before you can even think about changing anything else.
Do not forget that there are quite alot shenanigans going on with our ISPs and what they are doing that is totally out of our control. There is quite a big difference where you live and what options are available...from you have several connections options and several ISPs to choose from to basically there is only ONE option...
In America and Europe there is LOTS of IPv4 addresses, so it is very common that to get public IPv4 address...and here they generally do NOT embrace and deploy IPv6, since they have plenty of IPv4 addresses.... but they are running out of them too, so they are doing more and more shenanigans to overcome this problems...
In Asia/Australia/etc they have far less IPv4 addresses so here IPv6 and other measures are used to overcome this limitations... which making it harder and harder to write functional netcode...
So what this means is that there is alot things that your ISP can do with your traffic that can huge impact on things like how netcode in games works, and as "western" ISPs keep on denying their customers IPv6, then this is just a problem that is going to be more and more prevalent as time goes on.... Mobile internet (over mobile networks) are getting more popular, and what I have seen with these is that they are more and more NOT giving you a public IP-address, so going from your xDSL/Cable/Fiber connection to a Mobile provider does change things up.... in a negative way when it come this.
And this is where we end up in NAT nightmare.. since first, many have NAT routers at home... and some think that NAT is a security measure... to overcome NAT, we got idiotic stuff like uPNP, that nowdays is enabled by default by ISP delivered equipment...
Then we have Carrier Grade NAT, basically what your router does, but now your ISP does it on a much larger scale... so that now you could have TWO systems hiding your computer from direct access, making it increasingly harder to established direct connections... There are several tricks out there to overcome this, but as our ISPs comes up with new ways to do this on, things constantly breaks... like how netcode appears to be more buggy nowdays than before... could be the result of what our ISPs are doing...
So the bottom line is, it is hard to keep up, as long as we delay the deployment of IPv6, then IPv4 is going to be more and more messy....and FDev is embracing IPv6, but that does not sovle the issue if the "western" players don't get IPv6 addresses from their ISPs...And then they added NAT to IPv6... so we have already started to mess up IPv6 again....