https://www.sandboxx.us/blog/how-much-cheaper-is-the-f-15ex-compared-to-the-f-35/ The F-15EX does not boast any stealth capabilities, nor does it have the same knack for sensor fusion that has earned the F-35 the unofficial nickname of “quarterback in the sky.” Despite this apparent lack of capability, the Air Force is procuring F-15EXs at a cost of around $87.7 million each, as compared to the now lower F-35 price of just $77.9 million per aircraft. The F-15EX costs $87.7 million per aircraft, and can fly for up to 20,000 hours at a cost of $29,000 per hour. So $29,000 per hour x 20,000 hours + $87.7 million for the aircraft comes out to a pretty serious $667.7 million dollars." I think it takes about 400 hours of repair and maintenance per hour of flying time. You need to train your mechanics and avionics people to keep them flying, hundreds of hours. You need to buy ordinance that will fit on your Fighter jet, you need people who know to mount the ordinance. You need trainers to teach your pilots. Faugh!
The F-15 is probably still the go-to aircraft for launching an anti satellite package developed for it quite some time ago. Not sure, but it could be that you need a twin engine high speed interceptor to deploy that weapon.