A critical, and very value add service the LHS has historically provided is advice... replaced easily, and very effectively, by this forum.
The "You'll be sorry when your LHS closes" crowd is beating a dead horse. I'd guess the number of people that benefit directly from an LHS, but don't buy from it, is very minimal. Even within this small subset of consumers, I'm sure most understand the consequences of their choices... & presumably are okay with them. I'm probably giving consumers too much credit, but I can't imagine there are many out there that get upset when a store that they never bought from closes?
Now, I can see some merit in the argument that as more LHSs close, the hobby (& therefore the industry) is adversely impacted. Not necessarily from the standpoint of the current hobbyist in the short term (they'll know where to get everything they need), but from the standpoint of pulling new consumers into the hobby... which of course ensures the longer term viability of the hobby / industry (for all of us). This assumes LHSs are responsible for introducing at least some new people to the hobby on an ongoing basis.
Given the above is a reasonable assumption, the only realistic "fix" is on the supply side. Lionel, as the "big dog" needs to take the lead and protect the LHS channel (via fair / level wholesale pricing, retail price controls (think Bose, Apple, etc.), etc.). It might be tough in the short term... they could lose some market share (to lower priced MTH, Williams, etc.), but if anyone can do it, it's Lionel (brand loyalty, price elasticity v. other brands, etc.). The move could be worth it in the long run - healthy / fair margins for both you & your dealer network, actually having a network (other than a few large e-tailers), having what might be a dedicated / exclusive retail channel (if I'm a mom & pop shop & I have the choice of selling a Lionel at a decent margin, at the same price as a big internet outfit v. trying to sell an MTH item, at a low margin, competing with wholesaleblowout.com... which am I going to carry?). If it works, companies like MTH, Atlas, Bachmann, etc. might be forced to fall in line (or risk getting dropped by all their retailers... and going the "direct" route (like RMT recently did)).
Option B... which is probably more likely (based on what we see today), is that Lionel, MTH, etc. simply don't see much value in the LHS. i.e., The hobby / industry doesn't need them anymore. They see the future as either direct to customer over the net, or maybe utilizing a few big distributors to go direct to the customer. If your supplier doesn't buy into the value you bring to the table, you don't have much of a chance to succeed.