I've been riding tubulars for 45 years, and I've never used rim tape at all, just a few applications of glue with each new tire mounted. If you get a small tube of rim glue, it comes with application instructions. It's a tedious process to get right, and takes a few coatings over a day and a half or so. I've always done this, and never had a tire roll off.


Once I get too much old glue on the rims, I scrape it off; usually with a screwdriver, (a bit less likely to scratch the rim than a knife.) Sometimes some acetone on a rag helps. But new glue WILL bond to old glue; so no need to get the rims perfectly clean. And I've never seen rim glue disintegrate like you described with the rim tape; it just gets rock hard with age.