Just talking abstractly about “lumping” and “splitting” and “people out there somewhere” seems unproductive to me. It’s the nuanced details of how you decide to define a species that results in all downstream inflation. If we have problems with species inflation in general then we need to figure out at the source what is causing the problems and address them there. Are people just basing new species on percent difference in genome? Tiny variations in phenotypes?
I’m most with the general species concept with birds where there are overarching taxonomic authorities that have a fairly consistent method. Just from following North American bird taxonomy (overseen by the American Ornithological Society) for a bit over a decade I’ve seen enough edge cases discussed to know where the line is and generally it makes sense to me. American/Northwestern Crows and Thayer’s/Iceland Gulls were lumped recently, Pacific-slope/Cordilleran Flycatcher and the redpolls may be lumped in the next couple years. Discussion of splitting various species (Eastern Meadowlark recently, maybe Willet, Yellow-rumped Warbler, White-breasted Nuthatch soon…) has been going on for years.
The most important factor seems to have been detailed analysis of hybridization; how large the overlap zone is, how successful hybrid offspring are, etc. But because birds use vision and sound to communicate with each other, their appearance and sound tends to be correlated with reproductive isolation as well so identifiability is also a factor. Birds are relatively “large” animals too so subtle differences are easy to see.
I have no idea how you are supposed to determine those things when you’re studying insects or plants because they don’t necessarily distinguish among themselves using the same features we use to distinguish them (which also makes studying hybridization difficult I assume). You also don’t have overarching authorities who can have a consistent species concept and make authoritative decisions about the state of the literature. Personally in learning plants, invertebrates, herps, etc. through iNaturalist the species have generally made sense to me as being consistent with the species concept I grasped from bird taxonomy, they’ve just often been more frustrating to identify because they’re smaller organisms or use more obscure features to separate.