I've run 50:1 in all my Stihl saws and 2 Echo weed eaters, and 1 Jonsered brush cutter/weed eater for at least a few years. Recently I found a local NON-E-10 gas supplier, and now only use NON-E-10 gas. I don't store any gas in vented containers anymore. ALL the gas I use in my 2 strokes is available ONLY as high test; there is no low octane gas available as NON-E-10. One reason this is the case in VT, from my understanding, is that snowmobilers are a big contributor to our economy. So, between boating in spring and summer, (this year spring will occur around early June, and summer will end around mid-August; I STILL have snow on the ground!)

and snowmobiling from July 30th 'till heII freezes over... There is plenty of demand for E-10 free gas.
As to vintage cars, like T's and A's, they aren't 2 stroke engines; their engines were made of real steel, iron, etc. They ran on leaded gas, which coated the valves, etc.
Can't say whether detergent oils would hurt them or not, nor what to run for gasoline to get them the octane they need from what's available today. But, I seriously doubt their tolerances are that tight even after a rebuild- they didn't need to be back then, but I could be wrong, so if so, please feel free to correct my thinking.
With the last 20+ years of two stroke weed eaters/chain saws, etc. the metal used and tolerances are closer when new that ever before. Synthetic oil is a great improvement over everything prior, and allows for a lot of good outcomes that just weren't previously available. Synthetic oils have allowed manufacturers to guarantee saws for longer periods, when used exclusively with their specific brand of oil mix.
Engines run better in conjunction with synthetic oils and NON-E-10 gas. Everyone of my friends in the chain saw/weed eater, brush cutter, 2 stroke business, selling these tools, recommends 50:1 mix. I had a hard time at first thinking things specked to different ratios would stand up. They all have without exception. YMMV.