Everything is relative, i.e. perfection, darn good, good enough.
I have over 500 pre-recorded tapes, 7-1/2 ips. Inherited some, bought most on eBay. Played how many times?
Despite what people say, these tapes, and the Technics X2000r player are my best sounding source material.
I have many albums: CD; LP; R2R. Everyone picks LP over CD and R2R over LP, despite the fact that there is tape hiss in quiet passages and the S/N specs are worse than others.
Re-recording: IF the magnetic materials have not deteriorated, good to go. Repeated play, 60 year old tapes, no bleed thru, still sound better than other sources.
15 ips; 30 ips, gotta be amazing. I had a Teac that played 15 ips and 7-1/2 ips (they do not have 3-3/4 ips typically). I gave it to a musician friend and stuck with the X2000r (last pro-sumer deck Teac made). Plays big reela, 7-1/2 and 3-3/4. I do have some 3-3/4 ips, nowhere as good as 7-1/2, and LPs will beat them, but I can play them.
My tapes I made myself, FM simulcasts, still sound great.
like I said, if a perfectionist .....