I'll be very disappointed when podcasting becomes fully metricised. The large scale introduction of advertising will be toxic and do to this beautiful indie space what has happened to the web.
Would you rather the people who make quality podcasts have to spend the not-inconsiderate amount of time researching, rehearsing, performing, and editing alongside a full-time job? Would you rather they do that instead of making it a better thing?
Podcast advertising has been around for a decade and somehow, just somehow, it has not been as "toxic" as you imply.
It really depends. The problem is that once advertising become the primary drip of financial resources, the content begins to revolve around the needs, goals, and preferences of advertisers. Content that isn't seen as monetizable gets shown the door. Content that rails against consensus opinion or is anti-corporate gets shut down. Things that earn money get promoted at the expense of all else.
You can see this lucidly in the case of Bill O'Reilly. People had already known his deal for over a decade, but it wasn't until his ad dollars were pulled (after a public pressure campaign) that he was dethroned. That's an example of the kind of media system that is fostered by advertisement.
Hasn't advertising always been the primary drip of financial resources for podcasts? Aside from a bit more enthusiasm for Casper mattresses than is probably warranted, I don't think your concerns have come to pass.
The great thing that podcasts have going for them as a product is they're super cheap to make (relatively speaking). Podcasters willing to compromise the product by taking on more obtrusive advertising will get outcompeted by those who don't. It's ideally how media sites in general would work, but those are expensive enough to run that most sites resort to intrusive ads.
And when that state probably isn't economically tenable for the creators? Are you paying for everything you're listening to (you're almost certainly not)? For those you are paying for, are you paying enough to make up for everyone who isn't?
Like...podcasts are a lot of work for not a lot of return in the current environment. That's why advertising happens: because making a few hundred bucks an ep off of a preroll and a midroll, for a show with ten thousand active listeners or so, makes the argument for continuing to do it. Metrics are gonna keep mattering because it's the only way to make it a creative work that can at least pay for its time.