the cost of re-producing aGen 1 figure might be a lot more than a modern figure, Generation one toys were designed with much less modern materials in mind, they probably use a lot more plastic as it would have been more brittle back then and less plyable.
the toys themselves were a lot more complex (costruction wise) than many of todays toys are. an example would be an arm, a modern arm would consist of perhaps 5 parts that just clip together, shoulder, bicep, forearm hand, all with simple ball joint or rotating disc connections. an old G1 arm, upper arm, forward and back halves, lower arm forward and back halves, at least one pin for each of those joints, and probably a screw or two. probably 2 parts for the hand to slide into the arm. so maybe 8 parts.

I'm not saying all modern toys are much simpler but there is potentially a 30-40% higher parts count in a G1 toy compared to a modern toy where a lot of the joints are part of the pieces rather than an additional piece or more.
there is extra expense in the size of the mold to produce all the extra parts, assembly time, extra plastic volume to support the extra thickness, extra worldwide shipping/distiribution charges to cover the extra weight.

Having said that, i'd be happy to cough up a few extra dollars for a re-issue G1 figure especially if it's a dinobot or something along those lines that we've previously been given the impression we'll never see on a retail shelf again.