I don’t want to get married. - all of the rest of my post is kind of irrelevant because you don't have to if you don't want to. However...
I vehemently don’t believe in changing my name - I didn't and a good chunk of people I know didn't. Perhaps it depends on your social circle but it's definitely a lot less common nowadays
I am indecently pretty wealthy due to inheritance and my partner is not. - if you still wanted to be married you can speak to a lawyer about this aspect to protect your assets
It seems to me not a proclamation of love but a dated business transaction, one in which there is zero benefit to me as the wealthy party. - can't really make this as a sweeping statement (although I didn't expect to, I like the 'being a unit' feel of being married and it does feel different to before we were married, although that nice feeling alone wouldn't be enough to make me get married.) But it does feel like an emotional choice as well as a practical one for me personally. If it doesn't for you - i.e. you don't 'need' the emotional or romantic angle - then again, you don't need to do it if the rest isn't relevant or useful for you
I have read so much about people trapped in miserable marriages, and hate the idea of this ever happening to me. - generally when people are 'trapped' in marriages they are either emotionally trapped (i.e. don't want to leave because of children, social judgement, fear of being alone etc - which are things that could apply outside of a marriage too) OR financially trapped by being unable to support the lifestyle they need/want by themselves which it appears you wouldn't be. So it sounds as though this wouldn't be a concern for you - there's nothing un-do-able about marriage, if you have the will and financial means to undo it
Basically I don't think you're unreasonable for not wanting to be married, but some of your objections aren't really as big as you think. Regardless, it doesn't matter if your objections boil down to 'I don't fancy it' - you're allowed not to, there's no requirement to get married. Might be a tricky conversation if your partner does buy into the romantic or emotional aspect and it's important to them, but there's no better time to have that conversation than now - the longer you leave it, the worse it'll be if that's a dealbreaker for them.
I really like being married. I didn't expect it to feel as 'special' as it does - we got married mainly for practical reasons - but it does. If that angle on it isn't something that appeals to you/sways your decision, then it sounds as though it's not for you, which is fine.