A Google subscription would likely need to cost over $20/m - considering how many people wouldn't pay even one dollar for paid search. Google had $186Bn in revenue last year and ~1.8Bn monthly active users. The revenue comes almost entirely from search - with 1.2Tn searches per year - that's $0.15 per search - hardly anyone would pay that - and to get the same amount of revenue and profit with less users - they'd have to charge many many multiples of that. It's just not feasible.