Perhaps. Or we today make more out of it that it really was.
If you consider outside of context that "kaiden" means something like "all (is) transmitted", you could be quite right. Just because the teachings of a ryu were transmitted in no way implies that the recipient is some kind of expert.
However, in this context - especially in the last 60 or 70 years - the Menkyo Kaiden has
had a connotation attached to it that implies that the recipient has achieved an unusual, high, and sometimes coveted accomplishment.
It all comes down to the inside of the ryu as to what it may have as far as significance goes.
Another way Menkyo Kaiden is treated for example might be Hakkoryu. It's not unusual for a person to receive the "full transmission" license a short time after receiving the first teaching license. Having researched and practiced Daitoryu myself, I wondered about this and asked Okuyama Soke about it in 2000. His answer was something like:
"Don't worry. The licenses mean people have received the teachings. It's up to them to work on it for a long time. It would be a shame if only old people received the lessons, right?"
PS In Hakkoryu, Menkyo Kaiden lessons include a new set of techniques and also lessons about previous techniques, so it's another skill set that Okuyama wants to transmit earlier rather than later. This may be unique to Hakkoryu compared to Daitoryu, I don't know.