Yes, initial T-72 were outdated even in mid '80s, Yugoslav army used to modernize T-72 and produce their own MBT called M-84 which was 20% / 80% domestic/export production.
However, chassis is something that hasn't changed much and if it worked in '70 why wouldn't it today?
Take a look at the MiG-21, it's an 50 YO design that still works in practice.