While I can't speak for every Capcom game, the Capcom games I know about have experienced significant change or rennovation during their time.
Take Resident Evil; your right Resident Evil was selling brilliantly after Resident Evil 1, 2 and 3, and even Code Veronica was considered a good game. Capcom decided to go in a completely different direction with Resident Evil 4, and ended up developing what I would consider is the best or one of the best games in Capcom's history.
Reisdent Evil 4 was a reboot for the series, and its an amazing game, it stands as one of the finest games ever made. Yet there was nothing wrong with Resident Evil 2 and 3. Resident Evil 2 was the best game of it genre when it came out, even with that style stil intact, they still rebooted with Resident Evil 4 and achieved what they achieved.
The same story with Devil May Cry 4. DMC4 isn't really a sequel to the previous games. Its a different direction althougether. The game features a new main character, Nero, and features his girlfriend Kyrie. In what is a departure from the previous scripts of the previous games. The game itself says goodbye to Dante, and passes the torch onto Nero by the end. Thats how DMC4 was a departure from the previous games. Even the style was different, from the previous games. Where Dante was a bit more comical and less serious that previous games.
DmC is only part of a long line of reboots and directional changes that Capcom have made in the past. DMC4's sales were important, yet so was some of the negative feedback they recieved from the game.
You're right actually, thinking about it they do that a lot.(does'nt explain leaving the series dead for so long, or killing megaman though xD)
Resident evil 4 is defineitly one of the best games ever made(i've actually played it over 10 times XD).
I feel in that games case it managed to still capture the essence of the original series while heavily changing up the camera angle and gamplay, it's defineitly a more extreme case of change for a series but i'd still say that it had similiarities. I still had to scrounge around for ammo, the enviorment were still creepy and the breifcase function actually enhanced the management part imo, though 4 came out when I was 10 so I do have a hard time imagining it as anything other then a resident evil game now.
Also that might've been a case where they changed the core gameplay to stay relevant, most games with tank controls where being phased out, even silent hill's last game with tank controls was out by that point.
Resident evil 5 came along and changed pretty much everything for the series, the inventory management was'nt as good and the creepyness factor was gone completely, I think that's when people really started to complain.
As for DMC4, they clearly were trying to move it in a different direction or atleast experiment, however they still did keep Dante in the game and the previous story and gameplay, Nero is disliked enough as it is, i'm sure if dmc5 had instead been only about him people would've been fuming about it, maybe almost as much as DmC.
Dante was defineitly more comedic in that game but really compared to the rest nothing was personally at stake for him, his only reason for even being there was that he needed something to occupy himself and then through chance it turns out these guys have his bro's sword XD.
And a big part of the negative feedback for dmc4 was Nero and his prominence over Dante in the game, I don't understand why they would then think pushing it even further from the original series would help.
As I said in one of my previous posts, it's more just how much they changed it, dmc4 still had the type of humour, the music, the gameplay and of course dante and his personality. I feel like DmC pushed everything away from the originals, story, gameplay, music...
Experimentation is important for a games series however I think there's a point where a company is better off just making a new I.P.
like resident evil 4 I think another good example of this extreme experimentation would be metroid prime, it changed the series core gameplay over to first person but it kept the atmosphere and design close to the series roots, just adapted it to another type of gameplay.
Likewise, the new paper mario games(i'm a big fan of them and they just announced a new one that looks terrible) is an example of pushing it too far, the series thrived on it's comedy and storytelling but they've erased all that away in favour of a level system and no story.