I mean he has some merit though the machine has to be created first so they had to have not gone into the future the first time then they went to the future and went back into the past this is where they are at now because it has caused a loop that only Robin can get them out of with the knowledge of what they have tried before and what they do differently because it's the only way to explain how Fitz can sleep and enter timeline B.I believe you're mistaken. First what Robin said was "I haven't seen that yet". She said that in response to May telling her to keep talking about the way to save the world. May was telling her to give false hope at that time, knowing nothing would change.
The steps that took place from the team's perspective were:
1. The team goes to the future.
2. They talk to future Robin and go back to the past.
3. They go to the Lighthouse to get young Robin and her mother.
4. They try to prevent the end of the world based on what they learned in the future and from young Robin.
5. They fail and end up in the Lighthouse. 6. Fitz and Simmons design the time machine but die before they could build it.
7. Great value Starlord's dad builds the time machine.
Things start again.
There are clues that point to this being true. The biggest is when Fitz says you can't change time and points out that Daisy knew the consequences but still destroyed the world.