Everyone loves the old machines. They were definitely made quite well. But 50 to 80 years of use can wear them out. Many of them have seen continuous use for decades. Don't assume that a machine is super awesome just because it is old and heavy. If you find a machine that has seen decades of light to no use you can very likely have something excellent with a little work. But much of the old equipment that I have seen needed major restoration work before it would be useful.