I believe gin was originally an attempt to flavor a neutral spirit so that it would taste like a very well made new (that is, green, un-aged) whiskey or brandy. I say this because the flavors in gin are earthy, vegetal flavors, as you get in a low proof distillate, but one that is made so skillfully that only the most pleasant of those flavors are preserved. A less skillful distiller has to keep redistilling to achieve a spirit that is palatable, but then it is so neutral it needs to be flavored. It can be flavored with anything, of course, and the use of botanicals such as caraway seed or anise seed are examples of distillers using something simply because it tasted good. But I think the particular botanicals selected for gin, beginning with the juniper berry, were intended to duplicate flavors I also associate with young or even un-aged whiskey and brandy.
Even with the still technology of the 16th century, it was possible to achieve a very neutral spirit, though perhaps not as neutral as today's GNS. You just had to keep redistilling it. The best, most skillful distillers were able to produce, in fewer passes, a distillate that tasted good, and it was that distillate, that taste, that consumers wanted. But making that product took skill, while making a neutral spirit and flavoring it merely took perseverance, good equipment and a good recipe.
Gin got popular because it was cheap but tasted kind of like the rarer and more expensive low proof un-aged spirits that were the precursors of today's whiskey and brandy.
Another way of looking at it is rather than doing the delicate dance that distillers do, to preserve "good" congeners while eliminating "bad" ones, you can simply take them all out and put in flavorings that resemble the "good" congeners.