Let's look at when the Yankees were most successful in recent times (i.e. not the 1950s-1960s)
The free agent spending is part of it, but it is mostly smart drafting and trading.
The 1998 roster
-"Core 4" were homegrown talent developed in minors
-Tino/Wells/O'Neill/Cone were product of smart trades
-El Duque and Irabu they flexed their $$ muscles
When you simply start throwing money at the problem, you get contracts like Kevin Brown, or Cecil Fielder. Those bloated payroll rosters never got them over the top
If you want to make an argument for Cashman being the best GM, you need to look at his hot streak from 2015-2016. Dumping payroll. Remember Andrew Miller? Brilliance with signing Chapman, then getting Gleyber Torres from a Cubs team that was desperate to win the WS. That trade will go down in history
As a Yankees fan, it is really satisfying to have a roster with homegrown guys like Judge, Severino and Gary (before he sucked). And super smart pickups like DJ and Gio. Cole is the token big ticket free agent, and in that case it was worth it to get over the hump
That part matters. In the 1980s/1990s, all the haters would say the Yankees would simply outspend everyone else. Sure, I want to win, but it feels good to do it on a more level playing field
And the luxury tax is a salary cap of sorts. In some ways it is worse because you actually give money to the lower payroll teams.
I don't give Hal a complete pass. If DJ signs with the Mets, I will be livid. While George was an amazing owner overall, the Yankees had plenty of mediocre teams from the mid 80s until the epic 1996-2000 run. And I'm not sure if George would have been a successful owner in the luxury tax era. It is a different world.