I'm guessing you don't live anywhere near the station, nor have ever visited the area, nor have even read the Worcestershire County Council web page about the station... because that's not the case at all.
You wouldn't cycle along the "country B road" (the B4084) to get to Worcestershire Parkway. You would cycle along the signposted route which follows minor roads and traffic-free paths, entering the station on a specially provided traffic-free link from Woodbury Lane.
For example, from St Peters, you would follow the traffic-free paths; cross the bypass on a brand new £3m cycling bridge (opened earlier this year); follow the very lightly trafficked Brockhill Lane; then continue along the fairly quiet Church Lane (which includes a newly designated cycle lane along one section) to Woodbury Lane. You'd then take the new path into the back entrance of the station. All of this is signposted both as NCN 45/442 or as an explicit connecting route to the station.
Total distance, taking the Tesco in St Peters as a convenient reference point, is 2.5 miles.
https://cycle.travel/map?to=52.1561,-2.1606&from=52.1716,-2.2046
2.5 miles is well within cycling radius. There is plenty of research out there showing that sub-3 miles attracts a large number of potential cyclists and sub-5/6 miles still has significant modal share.