You expect office workers who get confused when an icon is moved to understand and use CSS for layout? Probably even Latex is easier for this.
And how can HTML5 do anything that Excel can do?
And how can HTML5 do anything that Excel can do?
2) HMTL5 can't do "anything Excel can do", which is why I didn't say it could. But a Google Drive spreadsheet can cover the needs of the great majority of people who need to publicly distribute spreadsheet documents.
There are definitely quantitative analyses that I would much rather do with Excel than with Google's HTML5 spreadsheet, but it's very uncommon to publicly distribute complex spreadsheets, and I'm talking about document interchange formats. The kind of spreadsheet you might embed on half of a page of a presentation is the kind of spreadsheet that HTML5 could easily handle.