This is a relative question.
With newer sites I find that no, you can't rank #1 in 6 weeks for extremely competitive terms like you could back in 2012, 2013, 2014.
With older / aged sites, preferably 6-9 months 1-2 years is really ideal.... these sites still won't rank "fast" if you're throwing young links (from young PBN sites) at them. You'll get movement. And you'll eventually rank. But it seems like the target sites don't rank until the PBN sites themself gain some age.
Where the slow down seems minimal (in competitive niches) is once you start throwing links from aged PBN sites at aged target sites. Then Google cooperates much better. In that instance my goal is to merely get the sites to page 2. Once I hit the top of page 2 I no longer "squeeze" sites to page 1 like I use to. I typically just wait a month (or 2) for the sites to settle. Then I add my first finishing touch. Where I just drop a few power links over the course of 1-2 weeks with some other weaker links. If you do it proper then you'll see that old 2013'd style ranking. Where you just wait now for Google to kick in. Then the site crosses page 1, to pos 9 to pos 6...5.... 3.... 2.... 1 all within 2 weeks without any additional links.
I think my sites are finishing like that (ranking faster on page 1 than any other page) since I'm aging some sites more than others. So links from aged sites do their thing and stabilize. Then I add my finishing round. But the younger sites from previous campaigns are aging around the same period I do my last batch of links. Which leads to a full on throttle that rockets sites quickly to #1.
That may sound nice but it's dangerous because you look like an idiot ranking that way. In certain industries its sketchy as hell. You have the "establishment" sites at the top. Not whitehat sites. But all these old authority sites that have been in relatively the same positions for years. Some franchises and national corps. Then your site comes out of nowhere trampling everything in it's path. Competitors will take note and begin stalking. Your shit better be in order if you rank that way.
The way I like to do it, although it's so hard cause you need to be super patient.... is to let your links fully "exhaust" at the bottom of page 1. Then you double, triple, quadruple check all your PBN security. I don't mean blocking link crawlers (I think that's useless). I mean go around sniffing out any little thing that smells of PBN. Redo whatever you need. Make your sites look commercial. Replace any low quality content with great writing and content. None should look like booster sites. If your WP usage is high, consider reverting to joomla or html. Consider replacing links. If I see too many home page links I'll move some to inner pages. If I see a site missing a logo, form, about, contact, anything I go and do all that first. Then once I know my PBN is rock solid secure from soup to nuts.... then I'll SLOWLY bring the site to #1. And I'll take my dear time since I know #1 already belongs to me long term. And just by ranking slow, when competitors eventually check my links they're more likely to think "shit, he's doing link exchanges or guest posts" vs "that's an obvious PBN let me report".
Because of that... I kinda like slower ranks now. It's forced me to stop taking dumb risks, it's made my SEO much more tight & consistent. When I rank now I'm not thinking "I need to rank by Jun 2016" I'm thinking "I'm gonna rank whenever I rank and I'm gonna do my links like it's 2020."
