By doing what, the same thing they're doing now on free over the air radio? People already know if they want to hear radio where to go.
Even though personal speaker sales are supposed to be huge this holiday season, I can see a huge backlash coming once the general public learns that these devices are harvesting data on everything you say in the home. And I mean, everything. If it detects a dog barking, you'll see a lot more ads for pet food and products from Amazon. These things make Facebook privacy concerns look like Fort Knox. Speakers aren't being offered because Google or Amazon are trying to be convenient, it's for harvesting your personal information and then selling you stuff. Of course if speaker users only read the fine print in the terms of use when setting up their Alexa account, they would see that they're signing all their privacy away.
And you're concerned that advertisers driving radio formats are a problem?
I doubt they really care all that much about data harvesting. Look at how many people use the internet, their smart phone -- all these other data harvesting mediums. Data harvesting hasn't stopped that. If they really cared about data harvesting and the potential bugging of their own homes, smart speaker sales would be zero.