I think that the cost of Opus is already prohibitively expensive, so not sure how that would compare to Mythos.
Check this calculator- it shows that a company with 100 devs can hit ~2.5M cost on tokens annually, which is wild!
https://ai-cost-calculator.arnica.io
A 100 dev team is going to cost on the order of $25m a year (keep in mind cost is not just their salary, but also the HR/Management org to support a team of that size, benefits, office space, hardware/software). So if you think you get a 10% boost in productivity out of Opus, its not prohibitive at all.
It's wild, but how many FLOPs in computation is occurring in those 2.5M in tokens doing? Might not sound quite as wild using that metric.