Why does koodo offer different plans to different people

Self Serve shows each account the plans it qualifies for. Your wife's sees the 40GB/$35 because her profile matches whatever criteria Koodo set (could be recent billing history, no Tab, or a targeted promo). Yours likely doesn't due to your pricier past plans or other account-specific eligibility. Out of curiosity, what is your current plan? What is your wife’s current plan? 

Interesting. 

We are both pre authorized payments with no tab owing. The online help person is unable to provide any explanation other than “ the plan you're asking about isn't listed in the rate plan change options available at this time”

even though is being offered because my wife just selected it this morning.

Wife was paying $53 for 9gb of data, 

I am paying $60 for 80gb.

That is not to say that you cannot try asking Koodo to match the same offer on your wife’s account. You can schedule a callback through Koodo Assist to speak with a rep. This entirely depends on the rep, so it is not guaranteed. Note that there will be a fee of $15 for the service. https://Koo.do/Chat 

They flat out deny any chance of matching it.

That is unfortunate. In that case, I would suggest you to wait until Boxing Day for better offers.

Is your account is on a legacy or grandfathered plan that restricts access to newer offers?  If it is, consider switching to a current plan visible to you; even if it means losing older perks; to access better pricing and data options.

Compare available plans in your Self Serve, or set a reminder to monitor upcoming promotions like Boxing Day for new offers.

No it is not a legacy plan, no restrictions or anything like that.

Yes, I always keep an eye out and upgrade my plan as offers better taylored to my usage appears, that is what upsets me with this. I want the plan my wife has access too, at this rate I will better changing providers for a plan that better matches.

I personally hate these personalized plans or offers.  Many companies in different industries do this.  I think it is discrimination.

In your case, it sounds like you are your wife have different account so it would be very difficult for them to match the plan.  If you were on the same account, there would be a higher likelihood (though still at the rep’s discretion) to match the plan for the other lines on the account.