The seats arent "business", its more a premium ecnomy product and fits well with the LCC model for JQ. loads are full and they are making money.
They dont have any option other than to invest in their widebody for the mid-life refurb as no one wants to buy a first gen 787-8 with no crew rest while many airlines are scrapping them.
XLR will take over most 787 routes with maybe their own premium economy, but yes they definetly need 3+ more frames