The shoot'em up, or "shmup" genre has a history as old as video games, dating back to the 1970's with Space Invaders, Galaxian, etc. In the 1980's and 1990's, games like Gradius, R-Type, Thunder Force, Soldier Blade and others were headlining home console offerings. It was a genre that had great prominence, and tapered off once the 3D era of gaming matured during the 6th generation of consoles.
The retro gaming scene has ballooned in popularity of late. Possibly due to kids growing up and yearning for the games that played in their youth, the rise of YouTube retro gaming content, and other factors, the resurgence has been palpable. This has led to increased numbers of rereleases and retro-inspired games on current generation consoles.
A recent poll (n=95) I conducted on the Shmups Facebook page indicates that the Playstation 4 and Nintendo Switch are tied as the favorite current consoles to play shmups on. This is surprising to me as there is some debate about the Switch's extra input lag when compared to consoles with more powerful hardware. For example, the Psikyo Collection Alpha has some of my favorite shmups, like Strikers 1945. I have this on PS4 and Switch. There is a noticeable difference between the two versions, with the Switch exhibiting more input latency than the PS4 version. I know this game like the back of my hand, having owned the original on Saturn for a long time. Perhaps the only people noticing this are people who have a long history with the game.
Fortunately, this is not always the case. In games like Ikaruga, which I have on Switch and PS4, I cannot notice the difference in latency between the two consoles. You would think that Ikaruga is a more demanding game (originally of the 6th generation of consoles, whereas Strikers 1945 is from the 4th/5th generation) so this is puzzling. The difference must come down to programming the ports. Maybe the team who programmed Ikaruga have better chops than the team that did Strikers. It seems that games programmed by M2 Shottriggers have the fewest latency issues on any of its ports, whether on Switch or PS4.
Many people participants cited the portability of the Switch as a deciding factor. People like to play in at work, during a commute, between classes, etc. While the idea of a portable console sounds good in theory, my eyes are not what they used to be, so squinting at small screens is not really enjoyable to me. If you don't mind small screens, more power to you.
Some have mentioned processing power favors the PS4, but this seems kinda silly when you consider that for the vast majority of shooters, 2 dimensions is the norm. We're not talking about system pushing specs and ray tracing for graphical fidelity here, nearly everything is sprite based. Even if there are polygons, the movement plane is still 2 dimensional, so any current generation system should be more than capable.
As far as game availability, it seems that amount of games released for both consoles are roughly equal. Besides a few exceptions, like Battle Garegga (2016) and Ketsui Deathtiny, games are now being developed for both. Many of these games are not physically released in North America, so importing games from sites like Playasia is a common solution. With shooters there is not much of a language barrier, and modern consoles are region free. Games are also released through small limited vendors like Limited Run Games, Strictly Limited, etc.
Being retro, there are people who prefer to keep it retro and play on as much original hardware/equipment as possible. CRT TVs and legacy consoles will always win the input lag test, so if that is what you're all about then you are not the primary audience here. Most people do not have the space (or family members willing to tolerate) for the extra bulk of CRTs. Consider also that old CRTs and consoles will start failing, and there are fewer and fewer people that can fix them. Parts are not being produced anymore, making maintenance even more of a hassle.
What do you think about the resurgence of shoot 'em ups on modern consoles? Are you fine with playing them on modern screens? Does the requisite amount of input lag inherent to modern consoles bother you? Do you mind buying these games again if you already own the originals?