Harder than it sounds. A complete drop-in replacement requires an almost unbelievable amount of internationalisation and research. And even if you can get all of that lined up, B2B sales and marketing - and inertia - are a huge challenge.

It's not that it couldn't be done, but it's very much a moon shot and it's not going to happen without someone charismatic and experienced driving it and selling it.

Specific niche feature SAP-a-likes are more plausible on a smaller scale, but sales and marketing will always be the real challenge.