"How much would it take to replace Excel with an open source alternative? $100K?"
That is one full time developer for a year, not counting any project management etc. If we say that so far, there has been spend 1000 man years on Open/Libre Office (I'm just making that number up, it has been under development for decades and probably with more than 20 devs working on it, so it's probably more, but let's say 1000, and not even count all the project management / user feedback / documentation work etc); then still you're saying that bringing Libre Office to the level of MS Office is within 0.1 resp 1 % of completion. I hope I don't need to argue how that is prima facie nonsense.
That is one full time developer for a year, not counting any project management etc. If we say that so far, there has been spend 1000 man years on Open/Libre Office (I'm just making that number up, it has been under development for decades and probably with more than 20 devs working on it, so it's probably more, but let's say 1000, and not even count all the project management / user feedback / documentation work etc); then still you're saying that bringing Libre Office to the level of MS Office is within 0.1 resp 1 % of completion. I hope I don't need to argue how that is prima facie nonsense.