Extract Ferm vs. All Grain Fermentation

So. All I do is read HBT while I'm at work and I love it but something has occured to me.

There are countless topics/threads/discussions regarding length of primary fermentation and length. We've all read it before so let's not go there.

But my question pertains to the fact that extended primary fermentation, anywhere from 2 weeks to up to a month is standard practice for those who have been doing this for a while. But if you've been doing this for a while, doesn't that probably mean that you're doing all-grain? Most of these questions about primary duration are about extract kits and brews.

Is there a difference, do you think, of length of primary fermentation for an extract vs. all-grain? Does it matter? For those who swear by/recommend/preach beautifully about how important it is for the yeasties to clean up after themselves: are you all-grain or extract? Both?

Just something I've been wondering.

Extract and all-grain fermentation is the exact same. Extract is a comercial, concentrated version of what is lautered from an all-grainer's mash tun.

If it is higher gravity, that means longer fermentation and conditioning...regardless of whether you buy the extract or produce it.

The difference lies with the mash prodecure. All-grain brewers can somewhat control the fermentability of their extract. Higher mash temps mean lower fermentability, and lower mash temps mean higher fermentability. If you buy extract, you only have one possible amount of fermentability.

Well I'm an extract brewer and I use the extended primary method. I usually go anywhere from 3-5 weeks.

For the record, I brew extract, partial and all-grain. Most beers sit in primary for a month, some low gravity session beers go 2 weeks at most (OG of <1.040)