Right, none of those have led to obsolescence even with long periods of time to grow.
Instead, think of replacements that have caused something to basically just disappear.
I'm not convinced this is the best example, but I think it helps get my point across. This is from a user's perspective, not a manufacturer's. Maybe someone can share better examples from software if these aren't appropriate.
When a new type of cable connector enters the market, it has to be at least as simple as the old one or do something more than the old one did. Serial or parallel plugs have screws to help hold the cable in place, newer plug types like FireWire or USB don't need the screws, so they are simpler. Now we are seeing new types of plugs that work "upside down" so they are even simpler for consumers to use.
I guess a better example might be media distribution. From a user's perspective, the compact cassette was just as simple to use as the 8-track. Or BluRay replacing DVD replacing CD.
Would high speed internet be as popular if it required a time consuming arcane ritual to establish a connection, compared to the simple bleep bloop of a dial-up modem?
So if you want the users of BGP (network operators) to switch to something better, make it just as simple for them to use, while providing additional benefits. Yeah it isn't easy, but it's certainly been done in other arenas.
Okay, SSH and Telnet. SSH is not as simple to use as Telnet. Windows users have to download a client, even in 2016. Server key changes cause warnings. People are often using encrypted key pairs instead of password authentication.
These (network admins who care about BGP) are sophisticated users. A secure version of BGP is not going to be as simple for them to use. It's just not happening that way, that's the way it always goes with security. More security makes the product more difficult to use, and a secure version of BGP is going to be more difficult to use.
Yes, you can find examples of simpler products that have replaced more complicated products, but that's rather poor support for the idea that replacements must be simpler or they won't be accepted. We're replacing magnetic strips with chip & pin for our credit cards, which are more complicated for everyone. Unencrypted HTTP may never completely die out, but HTTPS is everywhere and is only getting more common.
Or if you want simpler examples, think of the smart phone replacing the flip phone (less battery life, more complicated, more expensive) or the MP3 player replacing the cassette player (more expensive, more complicated, you have to get a computer and rip your CDs or buy digital music online). Or think of locks replacing simple latches on doors, now you need to carry a house key with you.
Or if you want examples more similar to BGP, think about spanning tree protocol. It's simple and it gets the job done. It's also completely dead in the modern data center, replaced by things like the far more sophisticated software defined networking. BGP is headed for the same fate.
Regarding need to download ssh, the same has been true about telnet since (at least) windows 7. (Telnet is NOT included by default in windows 7)
Warnings about server key change, is something i feel happens very rarely with a workaround described in the error message. I feel this is a very minor issue
The other ssh added complexity is optional stuff. and is something i feel made ssh better than telnet, example: You can forward X11 connection between unix machine using ssh.(Sure you use telnet and xhost/ DISPLAY et.c )
SSH-keys are also a optional feature, that are not forced on the user, but can simplify remote login.
Sure there are more complexity inside ssh and the protocol, but the simplest use of ssh is about as simple as telnet.
The protocol itself is a total mess. Having implemented servers for the Telnet protocol, I can say that Telnet is a little bit of a mess, but SSH is a total nightmare by comparison.
You're right though, that if you look at a very tiny slice of SSH then it almost looks like SSH is simpler than Telnet, once you've gone through the work of generating a key pair, securing the private key, and installing the public key on your server.
"SSH lets me communicate with a server securely, more simply than via Telnet."
By the same vein, HTTPS is "simpler" than HTTP in this regard.
Ditto for many possible BGP replacements.
SSH is more complex and more secure than Telnet.