Exporting large of amounts of data requires special handling by the web application so the user knows the excel export process is working.  With kendo-excelexport component, calling the save() function is where all the work is done and it doesn't return until the Excel file is complete due to it being synchronous.  There should be some way for the application to subscribe to progress events during the construction of the excel export process so the application can inform the user of this progress.