Using rubber and steel wires to manufacture hydraulic hose has been a technology in place since the early 20th century. Users of hydraulic hose wanted a product to be able to convey high pressure across a distance with the flexibility not found in metal tubing. Rubber was a natural fit for this application and worked initially by itself until the pressures required necessitated bracing the rubber with metal wiring for strength.
Over time, the multiple families of hydraulic hoses such as R1, R2, R12, R13, R15, R16, R17, and 4SH developed to suit specific applications and higher pressures. These hose families have not changed drastically in over 20 years as the OEMs that spec out hydraulic hoses have leveled out in their pressure requirements. However we should not be surprised to see new families of hose types arrive when larger equipment requires larger pressures to be managed.
What has changed, however, is the manufacturing process of hydraulic hoses. Both in material selection and processing. Hose and the metal reinforcement manufacturing is continuously improving to reduce defects as well as reduce costs. Rubber extrusion is used to manufacture the hydraulic hoses that we use daily and metal wire spindles are used to braid metal wire while metal spirals are formed around spindles. These technologies make hydraulic hoses more readily available to more consumers which in turn can reduce costs and open markets further domestically and internationally.