Specific SFR as a function of stellar mass, for the Model B predicted sSFR for NGC 300 (red solid star) and for the observed sSFR of xGASS and xCOLDGASS (Saintonge et al. 2017; Catinella et al. 2018). The solid line refers to the star-forming galaxy main sequence, and the grey shaded region represents the 1σ deviation (Eq. (2) in Catinella et al. 2018). Black filled circles refer to the observed SFR in nearby galaxies from xGASS and xCOLDGASS detections, while the grey filled circles denote non-detections in both xGASS and xCOLDGASS.