How does verilog deal with the fact that it doesn't allow user defined types

In reply to dave_59:

In reply to Yasmine4:
They move to SystemVerilog. It’s been widely available for over a decade now in ASIC development. All of the major FPGA development tools have broad synthesis support of user defined type between 5-10 years. Why not move up from Verilog?
Dave

Thank you dave, although moving from a language to another is not as simple as it looks, given the fact that there is a lot of old code that is still being used.