Four factors for a maker to consider:
-- Sometimes an offering, well-researched and well-planned, then well-advertised (possibly by free word-of-mouth), creates or expands marketplace demand by attracting new interest. What changed in Ireland and the Irish diaspora between the advent of ready-to-run models in the UK, Continent, and U.S. during the 1950s and the advent of small-batch kit-makers in the 1970s-1980s, then Murphy Models, Irish Railway Models?
-- Niche markets are only sustainable if potential buyers act upon their interests, or are able to act. Good intentions but no purchases pave a road to somewhere.
-- High-quality RTR will attract new buyers, because time and skill are scarce for working-age buyers. Quality and operability now can justifyt a premium price to overcome the obstacles of no time, inability to develop skills right now.
-- Models that allow a buyer to represent a "fleet" can encourage multiple "rolling" purchases by one buyer over time.
I'd love to see an RTR Irish 3-foot narrow-gauge locomotive for a "fleet" -- either Tralee & Dingle Hunslet or Donegal.