You see pretty much this exact post a couple times every season... and its pretty much always true.
Now there is obviously some benefit to getting your lanes ahead, and visiting top a couple times to get your guy shitting all over the enemy is great... That said, remember that ganking mid will allow your mid laner to get ahead, and then they can roam top, bot, or shove lane and help with objectives. Whats even more important is that 40% of your team is in the bottom lane, and if they lose it puts 40% of your team behind and puts heavy pressure on the drakes and more pressure on mid...
Camping top can help your top laner, and the jg get ahead, but when the enemy jg shuts down your bottom lane, and the enemy bottom lane starts pressuring your mid, and starts deep warding your jg and gets all the drakes... I mean, you must understand the investment involved in your gank choices over the course of the match. If you invest everything in top lane, and top lane can help with all the problems on the bottom part of the map, then that top lane investment will never pay off.
The point is ganks that put gold in your teams pocket, and take gold out of the enemy teams pocket are good, but like all investments, some are better than others. Getting 1% back on $1,000,000 is still more money back than an investment than gives 500% back on $1,000. 500% back is better in efficiency than 1%, but if you only have time to make one investment (and in this game you do only have so much time), then you want to make the one that will give a greater return.
Top lane camping is short sighted over all (it can have its benefits). Camping bot lane can have implications later like the first drake may be a wind drake, but the next two may be fire, and thats free % scaling stats. Those drake stats more or less belong to the team winning bot, and/or mid more or less. Top lane being strong has some influence on mid lane, and the jg a bit, but mid being strong has influence on top and bot, and jg... Since bot being strong has influence on mid... you get more overall synergy by putting your gank time in mid/bot portion of the map.
Now things are different every game, and your one trick Garen top laner getting fed out of control MAY be the best thing for the match, but that has be be balanced vs not putting your bottom lane well ahead when it comes to midgame.