Janeway also said in Season 7 ('Shattered' episode) the following:
'Voyager doesn't have an Astrometrics lab', after which, Chakotay said:
'Harry designed it, or WILL design it'.
I disagree with that it would have taken less time. I think the same number of people and resources would have been assigned to the task of upgrading the lab even at Utopia Planitia. Chakotay basically gave Kim carte blanche to the project, so Kim had all he needed to do the job, IMO. In fact, he thought the engineering team could really take over without him.
Not necessarily. There's a limited number of people from Voyager's crew that could work on the project at any given time, as other systems would need to be maintained as well and the crew needs rest. As such, the resources of Utopia Planitia would be higher, because you can have 10 teams working on 1 thing in various shifts, whereas on Voyager, only say 3 or 4 teams would be available for a project ... and you can also have a larger number of people per team at U.P.
As far as the Delta Flyer, I would liken that to being more akin to the construction of a car or van. It takes longer to develop and test the design than to really build it. The hardest part is getting all the parts.
Except that the Flyer was already developed/designed and tested in simulations, so they only had to build it.
Voyager as any SF ship would probably have the means to assemble a shuttlecraft... but it's entirely possible that that the ship would lack certain construction technologies that make the process more automated and instead, live crew was mostly required which probably slowed the process down.
But I do agree with the premise that the longest period of waiting would be down to designing/developing the ship - they already have the parts or can easily make them.
I disagree with this also. It took years to develop, build, and assemble the components of the International Space Station with the technology we have. I doubt that it really could have really been done in a few months. I also think that there are limits, even with 24th-Century technology, of how quickly certain things can be done. I think it's easier and faster to build small things than big things.
Building and assembling the components of the ISS took far less time than it took to design them.
Drawing boards take up most of the time...
Given our industrialized nature, it would be relatively trivial to build components for that level of technology since we had to follow instructions.
Furthermore, money dictates most of our limitations...
I'm not saying it would have been a 'snap', but I would say we could have done it a bit faster.
And besides, one would be wise not to take everything for granted that people in positions of power say about our technical capabilities... because if the governments want something done in a very short amount of time, people will find a way to do it, and they can easily 'throw money' into the mix to make it happen.
Of course there are limits to 24th century tech and that it's faster to build smaller ships (such as the Defiant) than a Galaxy class ship... but I'm also saying that what we saw on-screen was also very '21st century like' for the sake of drama.
Construction of the Flyer in U.P, would likely be faster because they have access to industrial grade replicators that can probably make things in larger quantities that regular replicators can't (in which case the crew would need to make smaller components and assemble them - in case of lacking automated facilities that would be dedicated to this work, manual assembly is needed).