Spreadsheet software and in this case specifically google docs are great tools for getting something off the ground fast; often it's good enough that no replacement needs to be written. I'm reminded of a contract some of my colleagues had at some point where a company's core business was all in a shared excel sheet, their job was to replace it with a proper application; iirc it took like 2-3 years to get it finished, at significant cost / investment. Of course, the excel sheet was no longer fit for purpose and not a good long term strategy to have.