The rules as they stand are with you, in my opinion: Arcade submissions are not excepted by the rules for "third-party" stuff and so "only" original components are permitted. However, you do point out that chip replacements are acceptable: which many other people consider "third-party". This is a third-party system which presents the same signals to the board as the original chip. Using a replacement cartridge which presents the same signals on the connection as the original is acceptable on "home" platforms and is allowed by the global rules: many adjudicators are well versed in seeing this.
The rules don't support this submission but multiple members of the adjudicators don't see the distinction between Arcade and Home (because it's just gaming machines). The rules can't be changed until TG staff acknowledge and consider if they need to be changed. TG will only consider that if this (or similar) submission is accepted and then disputed.
For those that wish to accept replacement cartridges and get the rules changed, this should be accepted and then disputed by those same people to get TG to change the rules.
For those that wish TG to re-affirmed that only original components should be used in Arcade machines, this would need to be accepted and then disputed by those same people.
It's all arse-backwards. ¯\_(ツ)_/¯