Right now we're pretending to not know the difference between old Soviet junk and modern tanks? But please entertain us with your version of why NATO is not sending modern tanks to UA? Perhaps they're too busy playing Dota? Or requests just keep getting lost? Or they can send millions of 155mm shells but logistics to send tanks are just too hard? Or they're secret RU Orcs too?
Right now you're pretending that NATO has only sent old Soviet era junk to Ukraine.
It seems like risk of escalation is not a major factor in why NATO has yet to send any modern tanks. It is *a* factor, as it would be an escalation, but not as big of a factor as long range missiles for example. Tank supplies are more limited compared to other weapons, they require more training and maintenance, and the US is concerned about transfer of technical knowledge of their Abrhams to Russia.
Also, Russia has been giving Ukraine more tanks than they know what to do with.