That's true, but my point is that the "Emperor is far away" problems can be found in any type of governing model. Some may limit it, but even then, there are tradeoffs.
One advantage of a centralized top-down system is that when an issue becomes sufficiently prioritized at the top, everyone below falls in line. The primary advantage here is speed and the ability to see through long-term plans. You see this in China's rapid rise in certain industries/technologies, and of course, in their response to the 2019-nCoV epidemic.
> In a localized bottom-up system, politicians advance their career by currying favor with voters by distributing handouts, like farming subsidies, tax cuts or artificially low prices.
I agree with this statement, generally, but there are many exceptions. Speaking only about politicians the US, at a certain level, further career advancement is also very dependent on currying favor with superiors (sometimes, even more so than currying favor with constituents, especially if one has national and not just local ambitions). This is equally true at the national level--see: the internal politicking within the DNC and RNC in terms of fundraising, toeing the party line, etc. to receive endorsement and campaign funds--as it is at the local level--see: "machine" politics like in Chicago, where advancement is equally, if not more, predicated on currying favor with your local party leadership and senior city politicians than it is with voters. Or course, this problem (in the US, at least) might also just be the results of our two-party dominated system, where party-endorsements trumps almost everything else when it comes to getting votes. To your point though, this can be overcome if you curry enough favor with the local voters (Trump himself vis-a-vis the RNC is a good example of this).