Yeah, I'm seeing that
I'm actually a bit unsure how to reply to that as you've effectively countered your own point but I'll try lol.
No, I'm not effectively saying that the original F-16 and F-16 Block 52 are same thing, I'm saying that (using your example) as the F-16 Block 52 is an upgraded version of the original F-16, it is possible to upgrade the original to practically the same standard.
That's the bit you're missing, you're looking at it as "ooh thing A is 30 years older than thing B so it must be 30 years behind technology wise" but you don't factor in that thing A has been modernised as part of a recent upgrade/repair process.
Okay, looking at Wikipedia's info (which will be a bit out of date for Ukraine as it doesn't include the refit programmes running over the past few years). They have the following active tanks:
Russia:
T-90: 370
T-80: 450
T:72: ~2000
Total: ~2820
Ukraine:
T-84: ~150
T-80: ~250
T-64: ~800
T-72: ~300
Total: ~1500
On paper Russia has a near 2:1 numbers advantage in tanks, however they are not going to send every tank in the country to invade Ukraine, so lets be kind to them and say they send half of them (again it's very unlikely they would send half of their entire tank inventory but as I said tis comparison favours Russia) that would mean that tank numbers are even between Ukraine/Russia, but Ukraine has the better tanks so all being even the tank battle would skew in Ukraine's favour unless Russia can manage air supremacy.