To answer the question, yes, that figure of eight cable will be somewhat detrimental to any xDSL service. How detrimental would be hard to quantify. The lack of a twisted pair allows extraneous signal pick-up. However, left undisturbed, such cadmium copper coated steel wire conductors are really quite heavy duty and strong. (Far stronger than any modern day 0.4 mm wire cored cables!)
The junction box is a good example of the type that was fitted during the 1930s to 1950s. (Approximate dates.) All it is doing is connecting the incoming service feed to the CW1308 specification internal cable. Why replace it when it is doing a perfectly good job?