I’ve seen Biden speak in person twice, once largely unscripted. He does better than I could. People underestimate how difficult speaking in public and while being recorded and scrutinized is.
To me Trump just sounds less enthusiastic than he did while President or at a candidate in 2016. But he still talks non stop for an hour +, which is also not an easy thing to do,
Biden is also compensating for a significant stutter. People always forget that he’s been battling a speech pathology for nearly 8 decades.
The hallmark of cognitive decline is always comparing one individual to their younger self. As you said, Biden has struggled with stuttering. He’s also infamous for going off-topic, rambling, and occasionally saying something a bit bone-headed. His ‘speaking gaffs’ were a major topic in 2008. Now suddenly they are “evidence of cognitive decline”. Malarkey! If anything Biden’s 2020 campaign was remarkably void of major gaffs, and he remains in good control of his stutter. He still goes off-script all the time, but that’s just who he is.
FWIW To me Trump sounds about the same as he did 10-20 years ago as well.
You can also tell though that they were limiting the number of appearances that he was making. There was a long stint of time where the only campaigning he was doing were scripted videos out of his house in Delaware. He's not completely gone mentally obviously, but he's not as sharp, and he's a bit slower.
That's not to say he's not doing well for his age or that he's unfit. I'm just saying that based on his current status, he's obviously using up his last years to be there. The presidency is draining enough for a 40 year old; a 78 year old though? I don't know any 78 year old that could keep going that hard and that long and actually perform their job in a meaningful way. So 82, yeah, even the healthiest 82 year olds I know are the ones that put a lot of energy and attention towards their health and don't work that kind of job. Even Bernie, as sharp as he is, I don't think he would've been able to do a 2024 run either.
Does anyone know any 85 year old that could navigate modern politics? It's just... too old no matter how healthy you are. Now if it's Trump v Biden again, no doubt, I'll take the old guy, but I hope Biden will step aside. Or at least run then, wink wink, step down a year or 2 in.
I'd say that Trump has also gotten noticeably worse over his presidency. What he said back in 2016 seemed pointed, well-messaged, and somewhat thought-out. I thought back in 2016, there was a good chance that Trump wasn't a buffoon, but a rather savvy politician. But his speeches now? I don't know. It's like he's such a narcissist, that 2020 broke his brain. His ego couldn't handle the lose, and it traumatized him sending him into a mental spiral.