Late to the party here as a newbie, but figured I'd my two pennies.
I'm in my mid-30s now. Grew up with cable in the house most of my life, we probably got it back in 1993-1994. We lived in Atlanta, so it was whatever MediaOne was before it was MediaOne. Through various acquisitions, that cable network is now Comcast. I moved out at 18, and never had cable again. At one point, the local cable internet provider was sending unprotected SD-quality QAM channels down the pipe, so we had totally free cable.. still didn't watch it. Neither me nor my roommates were sports fans - living in Pittsburgh at the time made that difficult because people look at you like you have two heads when you tell them you don't care about the STILLERS. There was just nothing good on.
Later on, the girlfriend and I got Netflix and Hulu, and that constitutes probably 95% of what we watch, which still isn't much. Plus whatever we get included with the Amazon Prime subscription. Over the holidays we decided to try a 1 month trial of YouTube TV, which as other people have mentioned, is pretty much just basic cable. I still haven't cancelled it because we DO occasionally turn it on and watch
something. We just moved into this new house with the pool (which is what got me here) and the old owners left a flatscreen TV mount on the wall in the living room. I decided it was time to upgrade from my 8 year old 50" Element from Walmart and get something nice. Picked up a 65" Samsung 4K QLED with most of the fancy stuff like HDR and a soundbar with Atmos.. I gotta say, it's pretty awesome looking and I'm not into that sort of stuff usually. TVs have definitely come a long way.
You might be surprised how that old antenna picks up digital tv.
You are spot on. Antennas are antennas - either they're in the right range for the frequency or they aren't. There is no special "HDTV" or "4K" antenna, and if someone tries to sell you one, they're being dishonest. Modern digital TV operates in the exact same VHF and UHF band as old school analog, they're just sending 0s and 1s through the air instead of an analog signal. That being said, most channels after the recent FCC repack are up in the UHF band, with only a few stragglers in VHF, so check to see what the actual
broadcast (RF) channels are in your market to make sure your antenna is best for what you're trying to pick up. Just because something says it's "channel 5" doesn't mean it's actually broadcasting there. For example, channel 4 (which would be VHF in the old school world) FOX DFW is actually broadcasting on RF channel 34 (UHF). You can see this stuff on sites like Antennaweb.org.