MS : moneyhatting, poor studio and IP development/management.
Sony : poor infrastructure design, waning interest in enhancing the consumer QOL experience as devices age.
Nintendo : zero desire to diversify their portfolio and appeal to other demographics, painfully insular management.
Yep plenty of ammo to go around for all 3 depending on the time.
MS - RROD, paywalling online gaming, microtransactions, that DRM stunt they allegedly wanted to do with the Xbox One, dropping all focus on games about halfway through the 360's lifespan in favor of third parties and the fucking Kinect, killed the spirit of Rare
Sony - PSN hack, also paywalled online gaming, killed PS2 BC in the PS3, YLOD, disc read errors on the PS2, shitty build quality on the early PS1 models (had to flip it upside down), DS4s having terrible drifting and early models having no battery life, "we can't put rumble in a wireless controller", $599 US DOLLARS, killing off creative studios for bigger and more profitable "cinematic" games, killing off the PS3 store and Thanos snapping 3 generations of games with it, shutting down the PSP store and turning that PSPGo into a paperweight, not supporting the Vita, Vita memory cards, PSP UMDs being generally awful and slow, Killzone bullshots
Nintendo - front loaded 72 pin connector on the NES that was prone to failure, "Don't use alcohol to clean your games so we can sell you cleaning kits instead", going with expensive cartridges or terrible small discs because "piracy", introducing gamers to the concept of a 'drought' between releases with the N64, the N64 controllers being entirely shitty from design to durability, putting a fucking handle on a purple console during the 'attitude era' of gaming, dropping core gamers like a sack of shit after grandma liked the Wii, making a non-HD console in an HD era, licensing endless shovelware on the Wii (DS too a bit), no free transfer of virtual console games from Wii to Wii U, friend codes, terrible online but still paywalled drip feeding and eventually killing off the virtual console, cheaping out on the internal memory on the Wii U necessitating the use of an external HDD, low res Wii U tablet screen, low res 3DS screen, Joycon drifting
edit: the "number" of grievances I have doesn't necessarily correlate to my opinion since some of these are way larger than others like the RROD, Disc Read Errors, and controller drift. Faulty hardware will always be my biggest issue.