Universities are not fast food restaurants, the reputation resides in the faculty, and they’re not replicable like fast food recipes or supply chains. “Harvard London” will be a completely different school with its own reputation (with a little bit of halo effect from the brand of course), just like no one mistakes UC Riverside for Berkeley. Unless you’re advocating for some remote teaching sort of deal.
Edit: In addition, some people only attend Harvard and co. for the networking opportunities.
"Unless you’re advocating for some remote teaching sort of deal."
I naturally expected that this would be the case. At the very least, record the lectures in 8K and stream them to other campuses (there would be major timezone differences).
Most successful franchises try to expand abroad. Why not build a Harvard branch in London, Dubai, Sydney, Mumbai or Tokio?
Each of those would likely be subject to some pressures over time, but those times and pressures would vary.
Nowadays it is a "all eggs in one basket" situation.