There are a lot of things that have improved cycling over the years. Here's my partial list in no particular order.
1) Integrated shift & brake levers. I believe the word for them now is "brifters"
2) Chainrings & cassettes giving riders of all abilities a wider range of gearing to use. Really helps on hills.
3) Frame material especially carbon fiber.
4) Carbon wheel sets.
As for the internet, it has made it easier for cyclists to gather together for common causes such as advocating for bicycle lanes and legislation.
Mobile phones and especially smart phones. Can call for assistance when needed or if there is an accident or to report unsafe drivers.