This is currently no possible, you could open an RFE for it.
I think a Screenshot or just sharing the Dashboard would be a better way to share the information anyway. Is there a specific reason you need it as text or excel?
Screenshot will not capture all information on the Purepath screen and sometimes you want to share the Purepath information with people not having access to Dynatrace at all (so sharing a link to purepath is not enough).
Yes that's a valid use case for sure. But I don't think a text/excel based export would do any good here. It's hard to get the PurePath information across in a pure text/table based style, as evidenced when exporting a AppMon PurePath Dashlet.
AppMon like session export would be a great way to share detailed information for analysis, can't imagin that's going to happen though.