I've no idea how long it took someone to produce a drawing of such detail and quality but I'm guessing it was measured in days, not to mention the years of training and practise that went beforehand. Such detail and quality is still available of course but now it's done by a machine in minutes or even seconds maybe, brought about by man's insatiable lust for speed, be it speed of production, process, travel etc..etc. The age where we can build a machine to do many a man's job and do it better and faster has been around for a while. It's just progress. IMO, artwork like that is worth far more than some abstract oil painting that looks like it's been done by a toddler in nursery school but is valued by the 'experts' in £millions.