20 years is an absurdly long time in tech
On other hand, America had more fibre than any other nation, but its hyperregulated telecom industry only managed to cross 10mbps averages 10-8 years ago.
20 years ago, Nokia 3310 was released.
For consumer hardware, that's still a very very long time to hold a patent on something.
Specialized scientific/industrial hardware, maybe... consumer goods... way too long.
But that's just my personal opinion.
Nokia probably had a gajillion GSM patents that they used to make the phone, and a bunch of other companies had to pay them money for many years to build 2g/GSM phones.
Qualcomm and a few other companies have a bunch of patent for 4g tech, so even now (when we're rolling out 5G), it's practically impossible to make a modern...ish modem without giving atleast some money to one of those companies, and 4G is "old tech" already.
FRAND is not with out its own problems, but it is alot better than the situation with eINK or 3-d Printers where there is not FRAND agreement
Now that is not to say I would advocate for complete removal of the patent systems but I do think Compulsory FRAND style licensing should be a requirement of obtaining a patent
Your distinction between Copyright and Patent is also strang as the suffer from the same flaw so it seems your only justification is that you believe 20 years is "reasonable" but Life is not
I think both are unreasonable, I would personally like to see both dropped to 10 years, or some compromise where you get 2-3 years exclusive use of the creation then have some kind of compulsory license where the creator is compensated but can not with hold the creation for 20 years (with some kind of scheme that the license be fair and equitable)
Patents can be useful as an incentive, but their length need to correspond with the pace of progress in a given field. Otherwise, they end up slowing down everyone.
Once you have proven the need for an exclusivity grant, You also need to prove that 5, 10, 15 years of exclusivity via a patent would be unable provide enough incentive, that it had to be 20 years to strike the proper balance
In today's fast moving society, I think 5 years would provide more than enough incentive even for expensive technology that requires lots of capital investment though I would favor a shorter exclusivity grant, and then may be longer required licensing grant. like 2-3 years of exclusive use, and then 10 years of licensing but the patent holder is required to treat all uses of the patent in the same manner with fair and non-discriminatory pricing.
I agree about copyright, though. Copyright has been expanded to cover software and even APIs. Copyright is a giant drag on innovation. A single company can tie up a space for life of the author plus 70 years, which is absurd. Copyright should never have applied to most forms of software, which clearly fall into the exceptions of 17 USC ยง 102(b). But we are where we are.