It does make a difference to have 5E explicitly under the OGL, though.
If I'm writing an adventure that involves a slightly customized lich, say, it'd be really handy if I could copy the lich statblock out of the Monster Manual and then tweak it to my needs, rather than having to rewrite the text of its abilities (to avoid WotC's copyright) and re-do the layout (to avoid WotC's trade dress). It'd also be nice if I didn't have to pre-emptively lawyer up, as most of the companies making "unauthorized" 5E content have done.
It does make a difference to have 5E explicitly under the OGL, though.
If I'm writing an adventure that involves a slightly customized lich, say, it'd be really handy if I could copy the lich statblock out of the Monster Manual and then tweak it to my needs, rather than having to rewrite the text of its abilities (to avoid WotC's copyright) and re-do the layout (to avoid WotC's trade dress). It'd also be nice if I didn't have to pre-emptively lawyer up, as most of the companies making "unauthorized" 5E content have done.
That's what I was saying. The OGL exists, so at this point they might as well embrace it and work with it to their advantage. The key to not creating another Pathfinder is to not give anyone a good reason to. And Pathfinder came about not only due to the players who wanted to stay with 3.5 instead of moving on to 4e, but because Paizo had built a business on creating D&D-compatible products and WotC was dragging their heels wih the 4e GSL. Putting out their own RPG line ensured that they wouldn't be dependent on WotC's business decisions.
One way to embrace the OGL is to really focus on creating products that players will feel compelled to buy. Everyone can print out the rules or look at them on a tablet, but a lavishly-illustrated, well-constructed book is difficult to produce on your own (or even for a smaller company) -- and they already seem to be doing this with 5e. Visual aids, maps, props, tokens, and the like make for an attractive product and are beyond the reach of companies working from smaller bugets and lower print runs.
It may not be a perfect analogy, but I think of it as being a bit like video game consoles. Bioware and Bethesda both make RPGs, and while one could think of them as competitors, a significant number of consumers buy games from both developers. Players who don't care much for action games but who enjoy RPGs and strategy games are unlikely to buy a new game console if only one company is making those types of games for it. When there are more RPG players buying game consoles, more developers will make RPGs for those platforms. Where there are more RPGs on those platforms, more RPG players will buy them. Nintendo has been struggling somewhat in this generation of home consoles in part because most of the support for the Wii U is in the form of first-party Nintendo games. They don't have the third-party ecosystem that Microsoft and Sony enjoy, which results in fewer games available, which in turn discourages consumers from buying the system, which discourages third-parties from developing for the system, and you get a continuous negative feedback loop.
Of course any time you have a relatively open platform, you end up with a few true gems amidst a massive pile of unadulterated crap (early 3e OGL products, Apple's App Store, etc). The lower the barrier of entry, the more low-quality products you are likely to see. Maybe WotC will have both commercial and non-commercial versions of the 5e OGL? So fans can freely distribute content that they create, but WotC could require an approval process for any commercial products. Every game that gets released on a video game console has to meet certain guideliness put forth by Nintendo, Sony, and/or Microsoft. The game cannot be published until the approval process has been completed. Perhaps WotC could have both free and premium versions of the commercial license, where the premium version has a faster turn-around and allows the use of the D&D name on the product.
I think that would be a reasonably fair arrangement. Fans could publish and distribute whatever they create, WotC could exercise some control over what gets released into the marketplace, individuals and smaller publishers wouldn't be locked out due to high licensing fees, and established publishers' track records would be more apparent by their use of the D&D name/logo (which would also increase the visibility of D&D products).