The whole concept of making a Marshall amp today is different than it was in the 60's and 70's. Marshall in those days was making amps and hoping to make enough money to stay afloat. Because they didn't have a lot of cash reserves they would buy parts as needed. If the supplier was out of the certain value or type they would just substitute another. So old Marshalls are inconsistent as are a lot of old things. Not all vintage Gibson and Fender guitars are great either.

Today engineers look at those great old things and go, how do we replicate that? Even better, they ask players what could be done to improve that old greatness. So now we have new amps that sound great but have the features we wished we had on our old amps. If the old amps were so great, how come we modded them? What's nice too is the amps cost less when adjusted for inflation than the original old amps cost in the day. I can remember in 1978 a decent guitar and amp was really expensive and you didn't have as many choices. Cheap guitars then were really awful as well.

We live in a golden age of equipment right now. I've never seen it so good.