Yeah pretty much that is what is going to happen. I really hope that 1st picture doesn't happen. That would be really bad.
You should really hope that the first picture does happen. I don't see the second one happening; the security behind other coins is not even remotely comparable to Bitcoin.
This also does not mean, that it will be the end of Bitcoin. We saw what happened last year when some unknown group flooded the network with transactions and called it a stress test. Most people just paid a slightly higher fee and their transactions went through quicker.
If this situation happens naturally without someone trying to force it to prove a point, the developers will react and a proposal will be suggested to increase the block size. This will receive consensus from the nodes and the miners more quickly, because it will influence their operations directly.
There are no urgency now, because we hardly see full capacity without these fake stress tests.
There is no urgency now and even if blocks were full this wouldn't harm Bitcoin in a way that people tend to say. They are being hyperbolic when it comes to the increase of the fees and possible damage to the network. They have no data to back up their assumptions, it is just speculation (usually). The people who were really affected by the stress test are people (mostly) who were did not include a fee at all or included a fee that was too small.