We use linen strings on bows 100# all the time. My buddy just made heavy bow 105#, it casts standart arrow 245 yrds or slightly more (glued bow) and he has linen string on it. He is also shooting rather alot, but linen string on his 100# "nuclear ash" single staev bow, which shoots around 220 yrds with standart holds since christmas and there is not significant wear apart of whipping, which can be repaired regulary.
If a bow loses weight significantly over period of shooting its badly done and not worth a dime.
The theory of "lighter than most people think" does colide head on with historical shot record, especially with recorded distances in Tudor archery and with weight of arrows which is known.
Again - well known law of Henry VIII. says something like this: "Item that no man shoots flighting or prickling arrow at any mark shorter than 240 yrds" (Reworded, exactly in Hugh Soar "Of bowmen and battles") which does not mean that they did not shot any shorter ranges, but heavy military arrow was required for them and that means 3-4 oz. Shooting light 2 oz arrow which is more appropriate for a bow of say 80# was only permited at marks longer than 240 yrds (which on the other hand is not doable with 2 oz arrow and 75-80#.
Later 1542 act says that a man over 24 years of age shall not shoot any marks shorter than 220 yrds. (Hardy+Strickland)
This is all clearly intended to preserve older tradition of shooting heavy bows and its not well doeable with 75# or similar weight.
Also the price of bows, particulary in comparition to archer day pay or even more stricking - to a craftsman day pay, is rather high and that shows it was not thow away item. I dont know what do you mean by "bows being short lived", but surelly a good bow has decent longevity and it can have 100 000 arows through it and still shoot reasonably. Military campaign was hard, but if your life depended on the weapon, sure you would pamper it?
There is zero evidence of archers using longbow with tied on dagger, I think its pure nonsense, they were relativelly well armed after all and no list of secondary archer weapons mentions such a provisorium.
Bows were eventually laid aside in "hand on phassis", but that does not mean they were not collected after that and also the english battle logistic was efficient in every point. Long marching campaigns in France did not often allowed for resupply even if arranged for.
You stress well "if it was availble to them" point. But even further - exotic woods became little more widelly imported perhaps at the end of 16. century when military archery was declined.
So self yew, self elm, self ash, perhaps yew backed yew is alright (as laminating yew on yew) does seem to start exactly the mment when good staves became scarce in 16. century. But there is no single such bow. (There is one from 17. and one from 18 century in archery hall in edinburg. (And these are lighter weapons of scotish origins made of yew backed with ash.)
Howewer there is zero evidence aside of ascham lamentation on pieced bows, by which he does thinks a repair of bad stave (such as scarf joint repair on one of MR bows.) There is written account of laminating bows from early 16. century, but that is continental, not english.
I cannot think of reason why a multilaminate out of exotic hardwoods or osage shall be called warbow, since its not one. Actually if made to originall shape, taper, tiler and measuremenst it does not work. These must be made different way.
J.