1) All expanses are stated at the table. We have very cooperative gaming groups where treasure is seperated in 7 parts. The 7th part is for group spending or if a character is a bit short on change. Book keeping on this matter is out of normal of what I do, but strangely I have two accountants in my groups (one in each) that love such accounting (and I mean realllllllly love that sort of thing). So we indulge them and guess what? Some of the other players are doing it too. Just in case that the rogue accountant is not totally honest...
2) The player was very well aware of the rule. We roll for who will choose first pick of character as we try to have balanced groups. It is the first time in 6 years that he gets to pick the wizard. He is a power gamer and a very good manipulator at that (no insult meant to him. He is quite good at debating his points, I mean, very good). He told me the rule was too strict and he wanted a, shall we say, exemption for him. Before I met all players I wanted advice on how people here see the rule. I should've given more details in the opening posts about the context of our groups, my mistake.
3) Yes the cost are a bit high but the campaign so far have been enjoyable by all players. Even the "power gamer". What costs you, you can charge to an NPC too. Services in downtime are resolve relatively fast, about 20 minutes per players. We use Xanathar's table as well as some old tables I did years ago and some others for temples, monasteries, baronies, thieves guilds and laboratories. Even living expanses are accounted for, as cash is very important to acquire for the above end game.
4) Many characters and groups ends with the ownership of a barony, temple, fiefdom or whatever. We usually do a few sessions and depending on the group's synergy and mood, we either end the campaign around level 15 or we go up to 20 if the characters would continue. We have had so far 5 different groups that went for the 20th level play. The rests stopped at level 15 when main campaign was achieved and castle and what not were build, up and running.
5) The rule in itself is a bit harsh. I know wizards are intended to be more versatile than the other casters. It was an attempt at reducing the number of wizards and it failed. Players are doing sorcerers and warlocks only for a little change of pace and only if there is already a wizard in the group. The utility spells that are brought into play by a wizard seem to be too good to pass on for my players. And I am not the only DM that sees this in his groups in my area. I have no trouble with wizards being so popular, but I would like to see more of the other casters into action to better judge what type of encounters will work best with them.
The rule is not to gimp wizards, the costs goes both ways as the characters can sell the right to copy from their spell book to NPCs. It is quite a common occurence that usually makes it equal to the other characters in terms of cashflow. The ink problem vanishes as soon as the character gets to about level 5. At this level, they have the inks prepared well in advance before adventuring. I reiterate that otherwise, the wizards is exactly as in the PHB.
Do you see this in your gaming groups? That is a predominance of wizards vs other arcane casters?
PS: And a vote passed that players, not me, decided to keep this rule (along with the expanses in upkeep and down time) 11 to 1. Guess who's the one was? And two other wizards voted on that.)
Edit: Modified the last sentence of #3 as it read weird. Damn autocorrector...