I didn't refer only to LSD but to all classic psychedelics. Still, LSD can "show you things".
Riba and colleagues (2006) conducted a SPECT study on ayahuasca, Tagliazucchi and colleagues (2014) a 3T fMRI study on psilocybin (actually same data like Carhart-Harris et al., 2014), Preller and colleagues (2017 ) a 3T fMRI study on LSD with meaningful music and Lewis and colleagues (2017) another 3T fMRI study on psilocybin with 2 sessions ≥ 10
days apart. Other studies of neural correlates are confounded by tasks or alike.
Also I didn't deny ACC deactivations. In fact, I'm familiar with them. Actually, combined with enhanced right insula activations, ACC reductions characterize switching brain states (Tang, Rothbart, & Posner, 2012) indicating brain entropy. Psilocybin is linked to decreased functional connectivity between prefrontal and parietal regions, including ACC and PCC (Carhart-Harris et al., 2012), But also, psilocybin connects conventionally segregated networks (Roseman et al., 2014) giving evidence against your thesis. Brain entropy can also be interpreted by also reduced current density in medial posterior and anterior regions when administering ayahuasca (Alonso et al., 2015; Riba et al., 2004). In addition, people who consume ayahuasca over a longer period show PCC thinnening and ACC diminution without neuropsychological impairements (Bouso et al., 2015).
You're right that neural functional segregation studies are very limited in their explanatory power and brain entros better to be investigated with functional integrity studies. However, neural correlates of psychedelic experiences can be utilized for neurofeeedback or TMS and maybe clinically valuable (Kober et al., 2017).
Not only does the DMN "collapse", but also the salience network (Lebedev et al., 2015; Tagliazucchi et al., 2016).
Furthermore, I didn't interpret the data here since I do my PhD on the topic around self-consciousness and psychedelics and don't want to spoil my thesis. If interested I can sePost too long. Click here to view the full text.