It goes both ways. And no - bot is not the lane that should generally be ganked early. Until level 6+, bot should usually not be ganked. Toplane is generally the best and easiest lane to gank early. Bot lane scales with items regardless of winning/losing lane; putting top or mid behind has a much bigger impact on their effectiveness - provided the losing lane (bot, top, or mid) plays intelligently. A bot lane that's ahead or snowballed early offers more damage and ability to push towers (depending on the other team's waveclear). A toplaner that's ahead offers comparable damage to a fed bot lane early/mid game, but they also offer much more durability - allowing for more diverse options. A fed toplaner early/mid will be able to completely negate a fed adc early/mid if the team plays properly. The same can not be said in reverse provided everyone plays correctly - until mid/late game. A fed toplaner can split and 1v2 the enemy jungle and toplaner or farm out vs the fed bot duo - giving his team a 4v3 if they group properly; which should allow them to win out over time despite bot being behind. The toplaner can also more easily rotate and force objectives since they can actually tank some damage and still fight if the enemy contests; adc cannot because the jungler would have lost too much hp and could get bursted as easily as an adc at that point since he would have been the only one tanking the objective. The toplaner can also pull several opponents to his lane, disappear, and tp to another lane to apply massive map pressure - bot can't do that. Or, he can go bot/mid, get off a gank or tower dive, and still tp back to his lane to protect his tower after having gotten his bot or mid back to even or ahead (if they were even to begin with). This can all be done with much more flexibility than what bot can do in early/mid game; making toplane the ideal role to snowball early depending on the matchup. Something like ornn vs maokai? No. Something involving a bruiser or fighter? Yes.
Mid takes second - by a decent margin - but still better than bot lane because a winning midlaner can roam TOP or BOT and shut down the other team in that lane - they have more rotation options on a short notice since they are in the middle of the map. And again, putting the other team's laner behind in mid means more than it does bot if the losing person is playing properly. The problem is - in bronze-gold elo, most bot lanes do not play appropriately. I had a game recently where my bot lane outplayed repeated 4v2 and 5v2 ganks and tower dives - trading evenly or nearly evenly. Because they played properly they bought time for mid and top and jg to take MORE elsewhere on the map than what they lost bot. And, it gave us REALISTIC opportunities to punish overdives by the enemy team with counter-ganks and counter-tp's bot which put our bot lane AHEAD. Just having tp up doesn't mean using it bot when they are being ganked will do anything for them. Bot has to play PROPERLY and WARD properly to enable their team to punish the other team for ganking. They have to accept that not every time they are ganked will they get a counter-gank or counter-tp. Sometimes it is better NOT to help. And if top or mid has been repeat ganked with no help given to them, don't expect them to drop everything the second bot is finally ganked - especially if it's the fed enemy support who has been ganking top or mid without warning. If you don't back up your jungler or warn when he might be getting invaded, don't expect him to jump to your rescue or sacrifice himself for you; after all, you refused to do it for him. Losing bot lanes can do just fine if they play smart. But that's just it - you have to play smart.
