I'm paying $65-$75 per month for two phones with plenty of data via Project Fi. So far the service is also excellent. You were saying something about all prices being the same?
I have Fi and love it, but it's not in the discussion for the level of data usage people are discussing here--your "plenty of data" is about 4GB/mo split between 2 phones ($20 for the first phone's voice/text, $10ish for the 2nd phone, leaving about $40 to reach your $70ish total).
The post you were responding to was talking about 100 GB plans to compete with the current 20 GB "unlimited" plans--even the latter would be $200/month on Fi, and 100GB at $10 each would be $1000/month at Fi's pricing.
Fi is awesome and cheap f you are usually on wifi at home/work and so don't really burn a ton of data on a regular basis, but it's not going to replace your wired network at home the way a cheap, fast 100GB/mo wireless plan could.