Has it been possible to churn this card in the past? Yes...
Can it be done as quickly and often as you suggest? IDK...
What we have done is get the card, with the 55K miles from sign up and min spnd, put around $5K spend on it, then add 20 K SPG points to get the 85K mile FC award ( it only takes 20K SPG to transfer to 25K LH). Cancel the card when the AF comes due, wait 6 months or so, then get the card again. We've only done this once (so two cards each, and two one way FC flights each, quite some time apart).
What I do know is that Barclays doesn't like to approve more than one card (of any type at all) per @ 6 months. And they are very unlikely to approve a new app for a type of card you still have open. Whether or not they will approve an app for a card you only had for 6 months, and just recently canceled is something I don't have any DPs on.
Especially if you have only the done min spnd on the previous card. I've always done monthly spend on every open Barclays card bc I want to be considered a 'good customer' when I apply again. Which used to be easy with the 'free MS' methods that no longer exist.
As for the expiration of the miles, they don't expire for 3 years. The way programs are devaluing, and as it gets harder and harder to even find available flights for awards, I wouldn't wait 3 years to use them. Especially since you can book an award almost a year in advance, so you really have almost 4 years to use the award.
We got our cards, and booked our one way FC flight when the points were less than a year old. We booked it nearly a year ahead, but the points don't 'age' once you book the flight with them. If you don't have SPG points to transfer, and so need to get two cards for one award, following the one year and 6 month schedule I wrote about above, you could still book your award when the points from the first card are less than 2 years old. It all depends on how patient you are I guess. We didn't mind waiting since we already had tons of points from AA, UA, SQ etc to use in the meantime.
