My doctor put me on low-dose MTX for this exact reason—here's hoping I never start to develop infliximab antibodies...
Regarding the price, I would also have to assume they're comparing generic v generic (even though generic adalimumab wasn't available in the US until this year!), so I wonder if the reason they're saying infliximab is more expensive is because of the associated nursing labor/infusion clinic/IV supply costs. I only paid five bucks for my meds at the last infusion, but had to pay $160 for them to infuse it in me!
Also, side note, the fact that a name-brand Humira pen "only" cost the NHS £400 in the UK (and likely cost even less for patients) is blowing my mind. They retail for about $3500 a pop here :(