Yes, they are harder to find now, we only considered floor plans with the main floor Master and love it.That was the same as his. Split level.
Today here they build them huge 2 and 3 stories but no master or full bath on floor one.
Like you said if you are older or have an injury you are done
Production Builders trying to cut costs, its easier and less expensive to stack homes onto additional levels and keep the foot print of the foundation smaller for equal square footage. People admire our home with master on the main when they see it and wish they had it, even 16 years ago when we built the house. (translated = younger people like it too)
Ps. I am with you, we do not like connecting bedrooms with a bathroom in-between. (referred to in some areas as a jacknjill bathroom)