D&D 5E Am I too strict?

[Helldritch]

Okay, just read the entire thread front to back. Started out pretty against Helldritch but am coming closer to his side here at the end (though still ultimately on the player's side). My campaigns are usually low on gold so this sort of rule in my game would give me a grand total of zero wizards which is what informed my original instantaneous disdain for the rule.
The things I would ask players to vote on are:
Would you like to spend downtime leveling up or spend gold on this chart to level up:
2: 100gp
3-4: 200gp
5-6: 300gp
7-8: 400gp
9-10: 500gp
11-12: 600gp
13-14: 700gp
15-16: 800gp
17-20: 900gp
Gold spent on this table can be put aside for armor, weapons, spell-scribing, or material components for spells but must be spent on your class features.

If the question is between training to level for everyone or gold to level for 1/12 classes obviously nearly everyone is going to choose gold for one class. If I asked whether we should double the price on all food or quadruple the price on apples I bet you'd get a majority of people saying apples.

Seems like a weird case though. I give Wizards 2 free spells per level as RAW and yet I've had 3 wizards since 5e came out and 4-8 each of sorcerers, bards, and warlocks. Charisma is just a way more useful stat than Intelligence in 5e.

Helldritch though, early in the thread it really sounded like you were asking for opinions when your mind was already made up which tends to create an environment less suited to diplomacy than is helpful.

Not a bad idea for the costs you give for leveling. A wee bit lower than what the players are spending in my games in the mid level and a lot lower at higher level. (But remember that they have castles, fiefs, thieves guilds, temples, monasteries, bardic school, barbarian tribe, druidic region and a lot of other stuff related to their classes) that brings in cash. The idea is where I will probably go to modify the rule.

As for the last part,
My mind was not made up, but during the posts, I talked to my other players. They voted and they decided to keep the rule.
I really wanted an opinion on the rule and not a judgment on my games or DMing style (a few posts commented things such as I would not get into your game, this is a horrible rule etc...). My games are fairly popular and they are often spectators in our bi-monthly friday night D&D (and it is never the same group twice in a row.).

I was really destabilized by the player that called me up on the rule for being too strict (as I said, he's a really good debater). I am not used to be so criticized as a DM. I wanted to see what were the opinions of most people on this forum. People that would care to give advice on the rule such as minor modifications, its complete removal (and why it should be removed) or getting it stricter/stronger. I should have mentioned that this rule costs cash to the wizard yes, but it can also bring in a lot of cash too if the wizard roleplays well. It is not a one sided rule. I see the majority does not like it but enough people gave me cause to ponder the rule and to prepare modifications to it not because they said it is a bad rule, but because they were precise enough with their critics. The rule will see modification in the next campaigns simply because some were posters were objective in their comments. The modifications will not be major ones, but they might mainly concern spell costs at various level.

I still do not know how I will convince my players to make more warlocks and sorcerers. These are made only if a wizard is already in the group (usually). My goal is to shake my players into new directions in arcane classes as these are the only two classes that are rarely used. The artificer is much more popular as he gets a good versatility for a "2/3rd" caster? Some of the suggestions in here were very good and in line with my usual way of DMing. In a few months, these will be brought to fruition.

Again, thanks to those that gave insight without judging.