I kinda somewhat reluctantly agree with you, and I think other commenters are missing the point that breaking up Google may allow non-US competitors to rise up and take Google's place on the world stage. Thus, breaking them up is not in the national interest of the US.
As long as there are many competitors, that's better than a monopoly, even if some of the competitors are foreign. Powerful monopolists restricting our freedoms is not in the interest of Americans long-term.
If Alphabet allows a non-US competitor to replace them, isn't it their fault for failing to compete? The threat of replacement is supposed to be what motivates Alphabet to innovate.
It could also be argued that allowing Alphabet to sustain anticompetitive damages is exactly what creates the opportunity for them to be replaced. Alternatives to AdSense and YouTube can only succeed in America if Alphabet rests on their laurels and is artificially defended from natural price competition.