The first thing you'll notice about this article is that the accompanying photo is NOT of vintage Star Wars action figures. Despite that false note at the outset, this is worth a look. From the piece:
Early in production, Kenner decided that the Luke Skywalker figure should have a telescoping lightsaber made of two distinct parts that would extend from the figure’s forearm. This feature was replicated for the Obi-Wan and Darth Vader figures but was quickly phased out due to fragility and difficulty in production. Kayleigh Francis of Aston’s Toy Auctions values this figure at £6000… with a whopping £7000 to £8000 for the Obi-Wan and Darth Vader versions.