There are plenty of counter examples to that, but that's not really the point. I vistied Wrigley Field last year, and they did a fantastic job refurbishing their classic building to keep its character, but bring it into the 21st century.
However, as I said, I'm in favour of a new build, but there are legitimate concerns about its design. I honestly can't think of any Scottish team that has moved stadiums (stadia?) in the past 20 or 30 years where I was impressed with the new one.
Forest Green Rover's plan for "Eco Park" is quite an attractive proposition, but that is budgeted at 100 million.
I also have less faith in the local authorities or government in providing the necessary levels of support it may need.
I do have faith in the current board to make good decisions, but any new build still carries mutliple risks, and mitigating those risks can lead to compromises we might not like.