Twitter shutting down legacy version is comparable to Flipkart and Myntra going app only e-commerce service for mobile devices in 2015. It allowed not only their rivals. Even smaller competitors to got to grew their market share. Seeing decline in customers Flipkart had to bring back their mobile site. Coming to Twitter many Windows Phones, old iPads and Gaming Device users will loose access to the service as they will have no official apps or browsers supporting the full version of Twitter. Leave alone users from poor countries where Internet services are below average and expensive. They uses apps like Opera Mini to save data. In many countries carriers collaborate with these browsers to sell their internet plans. Earlier India was one of this country. I think twitter needs to delay shutting down of their legacy service until for next 3 years atleast. Or it's gonna be facebook dominating in developing world.