Upkeep isn't much of an issue for most of us. The 'top' players in whatever sense have probably been around for a while; if they're playing their main or a frequent alt, they likely have enough gold stored up that they needn't worry about it.
And in any case, upkeep isn't an issue at all for a lot of builds, since many players choose lighter (and incidentally, cheaper) armor primarily for reasons of speed. You really only need to worry about it if you're going for a fairly heavily armored build and/or using the fancy horses. Sometimes newer players don't realize this since repair happens randomly, and all they notice is 'zomg, I just had to pay 3k gold for repairs!' - even though it may average out that they're actually still turning a profit.