It's 'make work' because it's a unnecessarily competitive system wherein prices will by definition be driven up to absorb all of the surpluses of any given business.
Google and Facebook are in the business of 'economic rent' of people's attention.
25% of sales price going to Google might leave 5% for manufacturer and possibly even more for the Ad channel. Aka 'Google is where most of your profits are absorbed'.
You're not competing against product competitors - you're competing for attention of individuals, which is very narrow, through a very small number of pathways wherein there are quasi monopolists.
Your 'competitors' are actually 'value chain competitors' - Google and Meta - in this case, who require you to pay extraordinary amounts to access their captured audience.
Google is a massively 'high margin' business, which is an indication of their market power in the value chain, and they could be much more profitable if they wanted to be.
Whatever you make - you are bidding against McDonalds, Mondelez and Proctor & Gamble, not your just your competitor.
To realize this power, do a little 'thought experiment' and imagine of the 'ad layer' of the system would commoditized and extremely efficient, due to heavy competition and/or 'good' regulation (or socialization). Say for example, people were served ads with perfect efficiency, and accounting for some kind of community/regulatory guidance - which meant that 'local services and companies' were guaranteed a tranche of time, along with public services and community things - like School events, local street plays, art houses.
This could probably achieved for a fraction of the cost in the system now, and it would mean 1) the profits parked at G and Meta would be distributed to other layers of the value chain - aka the advertiser/maker, manufacturers, parts suppliers, and also to consumers. 2) likewise a system that defies the 'race to the bottom' competition of advertising (imagine very simple, relatively cheap and authentic ads) and 3) the hidden surplus of the benefit of community awareness, issue awareness, which is invisible on the GDP because 'money does not change hands'.
Another way to put it, is that the 25% spend on Ads is mostly spent on 'economic rent' not really on the cost and effort associated with that activity, in addition to that system being extremely optimized for certain outcomes (profits for private enterprise) and not others (aka 'financialization' of social and community aspects).
All of the extra money, time and effort people have to invest in fighting with each other over very limited attention, through captured attention, is inefficient 'make work'. It's the 'private economy' version of the government paying people to dig holes and fill them.
In almost all areas where there is heavy economic rent, there are inefficiencies; Advertising and Real Estate are huge ones there, there are a few others.
Obviously, Google and Meta do 'real things' - they're not fake businesses, but the massive profits are an indication of the oligarchic power and it's definitely sub optimal.