A couple of very interesting points here...
I still can't stand Ragu, but since I no longer have a garden for fresh vegetables and don't can things myself, the difference between what I can do on the stove and what a $2.99 jar of sauce can do is pretty small.
I've found much the same in a couple of areas. A couple of years ago I started making all my own burgers, because I found that the quality was much better than I got by buying them (and I was
very glad of that when the horsemeat scandal hit!). I've recently made the same switch with fajitas, when I found a flavour combination that did the same. Conversely, I generally stick with store-bought curry pastes, because the difference in quality just isn't worth the difference in effort (thus far).
I think there's something similar at work with RPGs - I probably
could put together a homebrew system that would suit me a bit better than D&D 3.5e, but the reward probably doesn't justify the effort involved. (And, equally, D&D 5e needs to not just be a 'good' game, nor even 'better' than 3.5e. It needs to be 'better enough' to justify the effort involved in switching. A test, incidentally, that Pathfinder has already failed.)
I still add to the concoction more herbs, more garlic, sauteed onions, beef, etc.
That's also a good point: D&D, like a store-bought spahgetti sauce, doesn't need to be the end product - the user can (and probably will) further work with it, adding his own settings, stories, house rules, etc. WotC should (and indeed have) acknowledged that this will be the case, so can endeavour to build a system that facilitates, rather than hinders, the DM who wants to add more 'stuff'. (And that's likely to be an advantage of 5e over 3e or 4e, both of which were resistant to changes, either due to the inter-connectness of the system (3e) or the extreme utility of the DDI tools which didn't admit (many) house rules.)