In the early years of WS the market was awash with a lot of gear some of dubious quality (and all greatly inferior to today's kit) that probably did the sport no favours.
While there was 'universal' packaged kit in the early years even then there was the start of the proliferation of specialities as the sport sought to define its limits. I remember the contrast between regatta boards with fun boards that translated into the raceboards, slalom and surf gear. With sails there were fat heads, pin heads, and RAF and not long after-wards the cam sail. Fin design has of course come light years.
I note that for years there was pressure on *board to decline the supply of fins with its performance boards on the grounds that specialists do it better - for myself I still use my Drake fins but each to their own, but this is an example of the market speaking.
What has impacted on the sport is the reality that it is wind dependent and as noted on another thread it might not be the summer months when it is at its best, depending on where you live (and for the moment certainly not in the snow bound northern nations). Where I live this killed off the club racing scene. I know that in sub tropical parts of Australia the situation is very different - there is no universal best answer.
WS is at heart an experimental sport that adapts to its local conditions which is its strength rather than a weakness. Therefore putting a package together of sail/mast, fin, board and wetsuits is best done by simple observation of what the guys are doing on the water and then (importantly) working it through with the local WS retailer which would be the first port of call for newbies anyhow.