The phrase...
Morgan build the cars and the owners finish them.
is sometimes used.
Over the years many improvements made by non MMC people have ended up adopted by Morgan.
For 4 wheelers things like rear hoop/shocks to replace the lever arm system, bearings on the front hubs to lighten steering are just two. People like Librands, Mulfab, Sifab, Wolf are 4 who are prominent. There are many others including some regular TM contributors. Roger and his bump stops. DaveW has a big topic of his work. Phil Bleazely has done quite a bit of excellent work on M3W.
This subsequent improvement developed by non MMC people should really have been done by MMC themselves but it can be an expensive business. The early M3W issues were a clear example.
I remember the early Lotus Elans with rubber doughnut links in the driveshafts. They deteriorated . A company designed and sells new CV joint to replace it. The M3W Centa would be in the same design shortfall area but a non rubber doughnut to mechanical version is not impossible but probably expensive for limited number end use.
I also think early Mini front rubber cones could be replaced with more robust sprung systems that someone developed.

Plus Four MY23 Furka Rouge