A few points I think I'd like to make.
Yes, the spirit of modding is sharing. But I don't think that allowing people to sell those (exceptional) mods that are worth selling (I'lll get onto the 'worth' bit later) is necessarily a problem with the spirit of sharing.
Amateur photographers meet, comment on each others' work, swap tips on equipment or techniques, give advice to newbies... and those with enough skill and artistry (and the inclination) sell their photos. Not for a huge amount, in most cases, maybe not even enough to defray what they spend on equipment (let alone time).
Web-comic artists compliment each other on work done, include links on their websites to rival sites they admire, offer hints on technique, describe publicly the way they work, send fan-art to other webcomics, help each other out by providing filler content when an artist needs a holiday or is sick... and those who can (and wish to) sell merchandising, advertising space, printed books. Some put up a few chapters of their work on line, then the rest is only available (for a price) in print.
The point is, people don't inevitably and always become greedy, grasping and unhelpful just because some of them can make a little money from their hobby, and a very, very few can make their hobby into a career.
I see no reason, in principle, why modding for Elder Scrolls games (now and going into the future) shouldn't be sufficiently mature for those who can make a small (or even a lot) of money from their mods and who choose to do so, from existing alongside those who don't wish to make any money from their hobby, or who's work is too niche and specialised to command a large audience, or who have neither the time nor inclination to develop the necessary skill or artistry. And there's no reason why modders producing mods for free and modders raising some money from their mods shouldn't still help each other out.
Even if you say that modders charging money for their mods aren't sharing with mod users, considering the huge investment of time and effort into some mods, and the artistry and quality of those mods, even charging a very modest fee is still erring on the generous side. It's less in a spirit of sharing than giving away their work, but it is still sharing.
And, let's face an unpleasant reality here; the majority of mod users share nothing. Maybe a tenth will take the time to upvote. From Wrinkly Ninja's experience, maybe 12 out of more than a million will make a donation. From Emma's own comments, a fair number will only share demands and complaints. So let's not lionise any but the exceptionally generous mod user who takes time to courteously report on issues with a mod, or share a generous review.
Now, how recompensing mod users for their mods (for those who wish some recompense) is done matters. Right at the start of this fiasco I expressed serious reservations about how it was being done by Valve, and it turns out the reality is far worse. But that is a criticism of Valve's approach, their lack of thought and preparation, their grotesque misjudgement of the ES mod users (and perhaps modders), and their high-handed attitude when things were clearly turning into a disaster. It isn't a criticism of the basic idea of letting mod creators put a price on their mods.
And, finally, the knotty problem of 'worth'. How can one say one mod is more 'worthy' of selling than another. Basically, this has little bearing on intrinsic worth. It is entirely, I regret, about popularity. Yes, a mod that clearly has great artistic and technical talent put into it, as well as professionalism and quality control, is more likely to be popular than one that is an unmitigated heap of dreck. But no matter how good a mod is, if it happens to be doing something that few if any mod users want (or are willing to pay for) then it is unlikely to be 'worth' putting a price on. Sadly, some garbage is more saleable than art. That's human nature in a mass-market world. But it isn't, in itself, a reason to criticise or hound mod authors for wishing to charge for their work, nor is it a reason to stop them.