You asked OP if the woman in question was unreasonable to want to get married, quite clearly she is not, there are a number of excellent reasons to get married as noted on the thread.
He isn't unreasonable either if he really doesn't want to ever get married.
However it's not a good idea let this kind of issue roll on without resolution though, and it's a good idea to be honest with each other up front about future intentions.
It's their business however and no one else's.
Regarding your point about equal marriages. My DH and I have a very equal marriage.
When we bought our first house I put in a substantial deposit while he had no savings. He earned more than me in those days.
He had a serious illness, being his 'next of kin' could potentially been very important (I do know of partners whose in laws barred them from the hospital room)
We agreed that I would be a SAHM and so he was the sole earner for years.
I'm back at work and now earn a comparable salary to my DH but my job pays lump sum bonuses where as his doesn't.
We have always split everything completely evenly and considered all money as 'our money'.
He also participates in a fairly high risk hobby.
I adore my husband but there are a number of big decisions that we have made jointly in our relationship that I would not have made if we weren't married.
An 'equal marriage' doesn't mean continuously financially equal. Marriage gives a number of protections to us both.
The words of the marriage vows are there for a reason 'for better, for worse, for richer, for poorer, in sickness and in health' As much as we'd like to think that the 'worse, poorer and sickness' parts wouldn't ever apply to us, it's the protection for those parts that are important.