I disagree. Look at something like the Chicago el which is a true hub and spoke system. The el needs a ring line since any trip that doesn’t start or end in the loop generally requires taking the bus which is fine but not rapid transit.
By contrast look at the Yamanote line in Tokyo for a great ring that provides tons of connections and gets tons of ridership.
Beijing has 6 official ring roads. There is also a 7th but it isn't considered part of urban Beijing.
It really does suck. I lived between 3rd and 4th ring road in the eastern mid section (around san yuan qiao), and my work was on 4th ring in the northwest section in zhongguancun. So...around the loop I went, it makes the trip 20-30% longer. Line 10 (a loop line between 3rd and 4th ring, line 2 would be the inner loop around 2nd ring) theoretically takes me straight to work from near my house, but I almost never took it because it was just too long (and it was just easier to sit in a taxi on 4th ring if I timed my to work and from work time right).
I started my last stay there in 2007 (my first was in 2002), line 10 only just opened a couple of years after I moved there, let alone all the other subways that were no longer ring lines. Today is very different!
Back in 2002...I had to bus it to xizhimen a lot to grab a subway to sanlitun (forget the name of the station) on line 2! That sucked, but line 2 is a pretty small loop (so lots of time on bus). In 1999, my first trip there, it was only line 1 and 2, and line 1 was broken at Xidan (4th ring was also still a ditch they were building out). Fun times!
A ring is an important traffic egress/ingress source. More often than not, your destination is directly on the ring and you're not using it to make two connections, just one is sufficient.
Moscow inner ring has around the same number of stations than all the ones inside it (counting connections as one each)
