Interesting question - there were almost as many 141s as there were 143/144s, so I'm not sure that the "non-standard" situation was the whole reason for scrapping - BR did like ordering tiny non-standard fleets of awkward trains (a tradition that FirstGroup deserve "credit" for maintaining

)
Maybe the scrapping was more to do with removing the class in a hurry before Privatisation (and, if BR had continued then the 141s would have operated into the 21st century)?
Although, as ever, the "truth" with BR is always muddy - they had plenty of money to do some things but scrimped and save with other things!
By the end of the 1990s I think they'd done their job in terms of increasing ridership in West Yorkshire, and there were a limited number of routes where they were suitable due to their small capacity and longitudinal seating- you certainly wouldn't get away today with running a single unit on the Harrogate line in the evening peak, which was my last run with one of them.
There are certainly not suited to most services today, even at 1997 passenger volumes, but there are a number of routes in 2019 where a single 153 copes (not in
West Yorkshire, other than maybe Huddersfield - Wakefield, every other diesel services runs into Leeds nowadays, but we have had single 153s in Sheffield - routes like Doncaster- Scunthorpe or the Barton branch can cope with a single coach unit).
So, in a way, with 2020 hindsight regarding the increasing passenger numbers, it's a shame that thirty five 155s were chopped into single coach units (153s) only five years before the 141s were scrapped - I could make an argument that we should have kept the 141s in service and therefore "saved" more 155s to remain as two coach units?