@surreality I love that I'm getting a lot of time to discuss this and think about it.
Each dot on a character sheet represents an amount of XP spent with the exception of the fiat dots granted at character creation. If the amount of automatic XP granted is in excess of what is needed to support that, then it becomes immaterial. You will never lose those dots as long as you have the XP to pay their maintenance. Since the "soft cap" of automatically granted XP is arbitrary, to be set by whomever is running the game, that value could be just above chargen (effectively a 0 XP character) or a very powerful character (such as a 500 XP character).
I don't own VtR 2nd Edition, so I had to reference the Reno wiki for XP costs. If they're incorrect, please let me know. It looks like Blood Potency is 5 XP per dot and merits are 1 XP per dot, so luckily there's no equivalency there. If maintenance is 10%, and each XP is 5 beats, one point of merit is 0.5 beats to maintain (its own potential headache, but most MUs seem to have fractional XP gain already) and one point of Blood Potency is 2.5 beats.
Professional Training doesn't explicitly add merits, it gives the benefits of merits according to my reading and I admit that's a subjective difference. Regardless, you didn't "buy" the Contacts as a merit and you wouldn't pay for them that way with maintenance. You're maintaining those benefits by maintaining the merit Professional Training. That might make the coding for the accounting trickier, but that's implementation and not system. The same should be true for things like Mystery Cult Initiation and other group memberships that afford you benefits you didn't buy separately. It definitely wouldn't be fair to pay for it twice. CoD no longer gives an XP break to buying dots of an asset skill, either, but now grants a single beat when you purchase a dot. Could you play jump rope by decaying a stat and purchasing it back up? Sure, but it's not going to benefit you.
If it was viewed as maintaining your current abilities, the way you might keep going to the gym or regularly play trivia or do it every day as a part of your job, is that less egregious than viewing it as tax? I wonder if the connotation is offensive to some people, I mean, who likes paying income tax?
CoD, and other games like D&D or AFMBE or Shadowrun, seem to be designed around particular instances. This is the week where your pack of werewolves saved a town from predatory vampires, or the night you broke into ARES to steal a prototype of the new Predator pistol. They don't award XP for downtime. They award it for accomplishment. MUs, however, seem to award the bulk of their XP for downtime to represent growth as a person through day to day interactions. XP gained for participation is only a percentage of the total instead of the whole. A year long chronicle played twice a month covers a much smaller window of time than a MU that lasts a year, so it has no need to deal with maintenance. You don't have to buy more bullets, you don't have to pay rent for your house, you only do things for your allies if it furthers the story.
Paying maintenance represents all the things you have to do to stay where you are. Does that seem to close to RL? It can. I wouldn't want to do the math myself, at least not beyond a test case or three to prove my coding worked out. So I hear you, I really do. I brought it up here as a question about systems. It's about nitty gritty math and how do we advance and what does it cost us. I think there could be interesting ways to implement it, but that's a conversation for coding I think. Personally, I'd make a command like +stat/lock Computer and it calculates "Oh, you have Computer 5. That is 25 beats. To maintain, you need 2.5 beats" and it adds that value to the top of your sheet as XP Maintenance. You lock your important stuff, you see how much you "owe" and how much you have saved. Would that be a headache to code? Yes, and I'm not suggesting otherwise. This is not a "wouldn't it be cool if" scenario, or hunting for a reason to implement a formidable amount of code.
I do find it interesting that no one has mentioned respecs, because allowing stats to degrade and different ones to be repurchased seems like a rolling respec that doesn't break immersion.
...this was a lot longer than I anticipated. Sorry for the lengthy reply. I appreciate the feedback very much.