Ads have been around for a long time. If your great-...-grandpa bought a newspaper ad in 1820 he would have been looking to see if the ad worked (back then 90+% of people were farmers who didn't buy ads, but lets assume you had an ancestor then who was a shopkeeper and thus had potential value in ads). He probably didn't have have modern statistics, but he would pay attention to sales and try to figure out how much value the ad generated. (or he liked the guy who ran the newspaper and wanted to buy anyway...

If you are running ads you should be running statistics on them. You should know that you spent $X on ads, and got $Y on sales. This despite how messy the data is (Car manufactures want you to buy a new car every 3 years, so most ads are buy in the future not today - which makes getting answers hard). What matters isn't engagement, clicks, or any other data analysis can give you - they are (or trying to be) a proxy for what matters: how did advertisements affect sales. There are other ways to get that data, those ways have long been known. You shouldn't ignore them - if only to verify that that analysis is still working.